diff --git a/openerp/addons/base/ir/ir_fields.py b/openerp/addons/base/ir/ir_fields.py
index 302b11eb526..09622dadd17 100644
--- a/openerp/addons/base/ir/ir_fields.py
+++ b/openerp/addons/base/ir/ir_fields.py
@@ -184,7 +184,7 @@ class ir_fields_converter(orm.Model):
 
     def _str_id(self, cr, uid, model, column, value, context=None):
         return value, []
-    _str_to_char = _str_to_text = _str_to_binary = _str_id
+    _str_to_reference = _str_to_char = _str_to_text = _str_to_binary = _str_id
 
     def _str_to_date(self, cr, uid, model, column, value, context=None):
         try: