diff --git a/model/DataObjectSet.php b/model/DataObjectSet.php
index eb70f796c..decc1fcb2 100644
--- a/model/DataObjectSet.php
+++ b/model/DataObjectSet.php
@@ -5,7 +5,7 @@
  * @package sapphire
  * @subpackage model
  */
-class DataObjectSet extends ViewableData implements IteratorAggregate, Countable, ArrayAccess {
+class DataObjectSet extends ViewableData implements SS_List {
 	/**
 	 * The DataObjects in this set.
 	 * @var array
@@ -165,6 +165,10 @@ class DataObjectSet extends ViewableData implements IteratorAggregate, Countable
 		return $this->map($index, $titleField, $emptyString, $sort);
 	}
 
+	public function add($item) {
+		$this->push($item);
+	}
+
 	/**
 	 * Add an item to the DataObject Set.
 	 * @param DataObject $item Item to add.
@@ -529,6 +533,10 @@ class DataObjectSet extends ViewableData implements IteratorAggregate, Countable
 		return $output;
 	}
 
+	public function canSortBy($by) {
+		return true;
+	}
+
 	/**
 	* Sorts the current DataObjectSet instance.
 	* @param string $fieldname The name of the field on the DataObject that you wish to sort the set by.