diff --git a/lib/Alchemy/Phrasea/Databox/SubdefGroup.php b/lib/Alchemy/Phrasea/Databox/SubdefGroup.php
new file mode 100644
index 0000000000..0cc82d7f51
--- /dev/null
+++ b/lib/Alchemy/Phrasea/Databox/SubdefGroup.php
@@ -0,0 +1,115 @@
+<?php
+/**
+ * This file is part of Phraseanet
+ *
+ * (c) 2005-2016 Alchemy
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Alchemy\Phrasea\Databox;
+
+use Alchemy\Phrasea\Media\Type\Type;
+
+class SubdefGroup implements \IteratorAggregate, \Countable
+{
+    private $name;
+
+    /**
+     * @var Type
+     */
+    private $type;
+
+    private $isDocumentOrderable;
+
+    /**
+     * @var \databox_subdef[]
+     */
+    private $subdefs = [];
+
+    /**
+     * @param string $name
+     * @param Type $type
+     * @param bool $isDocumentOrderable
+     */
+    public function __construct($name, Type $type, $isDocumentOrderable)
+    {
+        $this->name = $name;
+        $this->type = $type;
+        $this->isDocumentOrderable = $isDocumentOrderable;
+    }
+
+    /**
+     * @return string
+     */
+    public function getName()
+    {
+        return $this->name;
+    }
+
+    /**
+     * @return Type
+     */
+    public function getType()
+    {
+        return $this->type;
+    }
+
+    /**
+     * @return bool
+     */
+    public function isDocumentOrderable()
+    {
+        return $this->isDocumentOrderable;
+    }
+
+    public function addSubdef(\databox_subdef $subdef)
+    {
+        $this->subdefs[$subdef->get_name()] = $subdef;
+    }
+
+    /**
+     * @param string|\databox_subdef $subdef
+     * @return bool
+     */
+    public function hasSubdef($subdef)
+    {
+        $subdefName = $subdef instanceof \databox_subdef ? $subdef->get_name() : $subdef;
+
+        return isset($this->subdefs[$subdefName]);
+    }
+
+    /**
+     * @param string $subdefName
+     * @return \databox_subdef
+     */
+    public function getSubdef($subdefName)
+    {
+        if (!isset($this->subdefs[$subdefName])) {
+            throw new \RuntimeException('Requested subdef was not found');
+        }
+
+        return $this->subdefs[$subdefName];
+    }
+
+    /**
+     * @param string|\databox_subdef $subdef
+     */
+    public function removeSubdef($subdef)
+    {
+        $subdefName = $subdef instanceof \databox_subdef ? $subdef->get_name() : $subdef;
+
+        unset($this->subdefs[$subdefName]);
+    }
+
+    public function getIterator()
+    {
+        return new \ArrayIterator($this->subdefs);
+    }
+
+    public function count()
+    {
+        return count($this->subdefs);
+    }
+}
diff --git a/lib/Alchemy/Phrasea/Media/MediaTypeFactory.php b/lib/Alchemy/Phrasea/Media/MediaTypeFactory.php
new file mode 100644
index 0000000000..33a351ce5f
--- /dev/null
+++ b/lib/Alchemy/Phrasea/Media/MediaTypeFactory.php
@@ -0,0 +1,37 @@
+<?php
+/**
+ * This file is part of Phraseanet
+ *
+ * (c) 2005-2016 Alchemy
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Alchemy\Phrasea\Media;
+
+class MediaTypeFactory
+{
+    /**
+     * @param string $mediaType
+     * @return Type\Type
+     */
+    public function createMediaType($mediaType)
+    {
+        switch (strtolower($mediaType))
+        {
+            case Type\Type::TYPE_AUDIO:
+                return new Type\Audio();
+            case Type\Type::TYPE_IMAGE:
+                return new Type\Image();
+            case Type\Type::TYPE_VIDEO:
+                return new Type\Video();
+            case Type\Type::TYPE_DOCUMENT:
+                return new Type\Document();
+            case Type\Type::TYPE_FLASH:
+                return new Type\Flash();
+        }
+
+        throw new \RuntimeException('Could not create requested media type');
+    }
+}
diff --git a/lib/classes/databox/subdefsStructure.php b/lib/classes/databox/subdefsStructure.php
index b1977724e0..938ba1c291 100644
--- a/lib/classes/databox/subdefsStructure.php
+++ b/lib/classes/databox/subdefsStructure.php
@@ -8,14 +8,16 @@
  * file that was distributed with this source code.
  */
 
+use Alchemy\Phrasea\Databox\SubdefGroup;
+use Alchemy\Phrasea\Media\MediaTypeFactory;
 use Symfony\Component\Translation\TranslatorInterface;
 
 class databox_subdefsStructure implements IteratorAggregate, Countable
 {
     /**
-     * @var array|databox_subdef[][]
+     * @var SubdefGroup[]
      */
-    protected $AvSubdefs = [];
+    protected $subdefGroups = [];
 
     /**
      * @var TranslatorInterface
@@ -33,22 +35,20 @@ class databox_subdefsStructure implements IteratorAggregate, Countable
      */
     public function getIterator()
     {
-        return new ArrayIterator($this->AvSubdefs);
+        return new ArrayIterator($this->subdefGroups);
     }
 
     public function count()
     {
         $n = 0;
-        foreach ($this->AvSubdefs as $subdefs) {
+
+        foreach ($this->subdefGroups as $subdefs) {
             $n += count($subdefs);
         }
 
         return $n;
     }
 
-    /**
-     * @param  databox $databox
-     */
     public function __construct(databox $databox, TranslatorInterface $translator)
     {
         $this->databox = $databox;
@@ -59,16 +59,14 @@ class databox_subdefsStructure implements IteratorAggregate, Countable
 
     /**
      * @param string $searchGroup
-     * @return databox_subdef[]
+     * @return SubdefGroup|databox_subdef[]
      */
     public function getSubdefGroup($searchGroup)
     {
         $searchGroup = strtolower($searchGroup);
 
-        foreach ($this->AvSubdefs as $groupname => $subdefgroup) {
-            if ($searchGroup == $groupname) {
-                return $subdefgroup;
-            }
+        if (isset($this->subdefGroups[$searchGroup])) {
+            return $this->subdefGroups[$searchGroup];
         }
 
         return null;
@@ -78,55 +76,36 @@ class databox_subdefsStructure implements IteratorAggregate, Countable
     {
         $sx_struct = $this->databox->get_sxml_structure();
 
-        $avSubdefs = [
-            'image' => [],
-            'video' => [],
-            'audio' => [],
-            'document' => [],
-            'flash' => []
-        ];
-
         if (! $sx_struct) {
             return;
         }
 
         $subdefgroup = $sx_struct->subdefs[0];
 
+        $mediaTypeFactory = new MediaTypeFactory();
+
         foreach ($subdefgroup as $k => $subdefs) {
             $subdefgroup_name = strtolower($subdefs->attributes()->name);
+            $isDocumentOrderable = isset($subdefs->attributes()->document_orderable)
+                ? p4field::isyes($subdefs->attributes()->document_orderable) : true;
 
-            if ( ! isset($avSubdefs[$subdefgroup_name])) {
-                $avSubdefs[$subdefgroup_name] = [];
-            }
-
-            foreach ($subdefs as $sd) {
-                $subdef_name = strtolower($sd->attributes()->name);
-
-                $type = null;
-                switch ($subdefgroup_name) {
-                    case 'audio':
-                        $type = new \Alchemy\Phrasea\Media\Type\Audio();
-                        break;
-                    case 'image':
-                        $type = new \Alchemy\Phrasea\Media\Type\Image();
-                        break;
-                    case 'video':
-                        $type = new \Alchemy\Phrasea\Media\Type\Video();
-                        break;
-                    case 'document':
-                        $type = new \Alchemy\Phrasea\Media\Type\Document();
-                        break;
-                    case 'flash':
-                        $type = new \Alchemy\Phrasea\Media\Type\Flash();
-                        break;
-                    default:
-                        continue;
+            if (! isset($this->subdefGroups[$subdefgroup_name])) {
+                try {
+                    $type = $mediaTypeFactory->createMediaType($subdefgroup_name);
+                } catch (RuntimeException $exception) {
+                    // Skip undefined media type group
+                    continue;
                 }
 
-                $avSubdefs[$subdefgroup_name][$subdef_name] = new databox_subdef($type, $sd, $this->translator);
+                $this->subdefGroups[$subdefgroup_name] = new SubdefGroup($subdefgroup_name, $type, $isDocumentOrderable);
+            }
+
+            $group = $this->getSubdefGroup($subdefgroup_name);
+
+            foreach ($subdefs as $sd) {
+                $group->addSubdef(new databox_subdef($group->getType(), $sd, $this->translator));
             }
         }
-        $this->AvSubdefs = $avSubdefs;
     }
 
     /**
@@ -137,11 +116,10 @@ class databox_subdefsStructure implements IteratorAggregate, Countable
      */
     public function hasSubdef($subdef_type, $subdef_name)
     {
-        $type = strtolower($subdef_type);
-        $name = strtolower($subdef_name);
+        $group = $this->getSubdefGroup(strtolower($subdef_type));
 
-        if (isset($this->AvSubdefs[$type][$name])) {
-            return true;
+        if ($group) {
+            return $group->hasSubdef(strtolower($subdef_name));
         }
 
         return false;
@@ -159,22 +137,26 @@ class databox_subdefsStructure implements IteratorAggregate, Countable
         $type = strtolower($subdef_type);
         $name = strtolower($subdef_name);
 
-        if (isset($this->AvSubdefs[$type]) && isset($this->AvSubdefs[$type][$name])) {
-            return $this->AvSubdefs[$type][$name];
+        $group = $this->getSubdefGroup(strtolower($subdef_type));
+
+        if (!$group) {
+            throw new Exception_Databox_SubdefNotFound(sprintf('Databox subdef name `%s` of type `%s` not found', $name, $type));
         }
 
-        throw new Exception_Databox_SubdefNotFound(sprintf('Databox subdef name `%s` of type `%s` not found', $name, $type));
+        try {
+            return $group->getSubdef($name);
+        } catch (RuntimeException $exception) {
+            throw new Exception_Databox_SubdefNotFound(sprintf('Databox subdef name `%s` of type `%s` not found', $name, $type), $exception);
+        }
     }
 
     /**
-     *
-     * @param  string                   $group
-     * @param  string                   $name
-     * @return databox_subdefsStructure
+     * @param string $group
+     * @param string $name
+     * @return self
      */
     public function delete_subdef($group, $name)
     {
-
         $dom_struct = $this->databox->get_dom_structure();
         $dom_xp = $this->databox->get_xpath_structure();
         $nodes = $dom_xp->query(
@@ -189,8 +171,8 @@ class databox_subdefsStructure implements IteratorAggregate, Countable
             $parent->removeChild($node);
         }
 
-        if (isset($AvSubdefs[$group]) && isset($AvSubdefs[$group][$name])) {
-            unset($AvSubdefs[$group][$name]);
+        if ($this->hasSubdef($group, $name)) {
+            $this->getSubdefGroup($group)->removeSubdef($name);
         }
 
         $this->databox->saveStructure($dom_struct);
@@ -199,10 +181,9 @@ class databox_subdefsStructure implements IteratorAggregate, Countable
     }
 
     /**
-     *
-     * @param  string                   $groupname
-     * @param  string                   $name
-     * @param  string                   $class
+     * @param  string $groupname
+     * @param  string $name
+     * @param  string $class
      * @return databox_subdefsStructure
      */
     public function add_subdef($groupname, $name, $class)