diff --git a/product/ERP5Type/Accessor/Category.py b/product/ERP5Type/Accessor/Category.py
index 6b3d87bad395be90c0aac2c2a2c3a466ecf6b2d7..bdbefba1301a84ab8ea81b6eb2c9ad81c0629638 100755
--- a/product/ERP5Type/Accessor/Category.py
+++ b/product/ERP5Type/Accessor/Category.py
@@ -169,7 +169,9 @@ class ListGetter(Method):
       self._key = key
 
     def __call__(self, instance, *args, **kw):
-      return instance._getAcquiredCategoryMembershipList(self._key, base=0, **kw)
+      if not kw.has_key('base'):
+        kw['base'] = 0
+      return instance._getAcquiredCategoryMembershipList(self._key, **kw)
     psyco.bind(__call__)
 
 SetGetter = ListGetter # XXX ERROR