Index: lib/filter/doctrine/BaseFormFilterDoctrine.class.php
===================================================================
--- lib/filter/doctrine/BaseFormFilterDoctrine.class.php    (revision 20489)
+++ lib/filter/doctrine/BaseFormFilterDoctrine.class.php    (working copy)
@@ -10,8 +10,48 @@
 {
   public function setup()
   {
+    $this->addAutocompleters();
+
+    parent::setup();
   }

+  protected function addAutocompleters()
+  {
+    $classes = array(
+      'sfGuardUser' => 'user'
+    );
+
+    foreach($this->getFormFieldSchema() as $name => $field)
+    {
+      $widget = $field->getWidget();
+      if ($widget instanceof sfWidgetFormDoctrineChoice)
+      {
+        $options = $widget->getOptions();
+
+        // we don't want to replace widget for this model
+        if (!isset($classes[$options['model']]))
+        {
+          continue;
+        }
+
+        // customized query, do not replace the widget
+        if ($options['key_method'] != 'getPrimaryKey' || $options['query'] != null)
+        {
+          continue;
+        }
+
+        // replace the widget by a sfWidgetFormJQueryAutocompleter
+        $this->widgetSchema[$name] = mrForm::getAutoCompleteWidget(
+          $classes[$options['model']],
+          'sfWidgetFormJQueryAutocompleter',
+          array(
+            'value_callback' => array(Doctrine::getTable($options['model']), 'getVisibleValue')
+          )
+        );
+      }
+    }
+  }
+
   /**
    * @see BaseFormDoctrine. (this is copy base paste to override the limitation
    * of the shitty inheritance of doctrine forms in 1.2)