Index: ucs-school-lib/python/models/attributes.py
===================================================================
--- ucs-school-lib/python/models/attributes.py	(Revision 72938)
+++ ucs-school-lib/python/models/attributes.py	(Arbeitskopie)
@@ -184,6 +184,7 @@
 	udm_name = None
 
 class SchoolClassesAttribute(Attribute):
+	udm_name = None
 	value_dict = True
 
 class SchoolClassAttribute(Attribute):
Index: ucs-school-lib/python/models/user.py
===================================================================
--- ucs-school-lib/python/models/user.py	(Revision 72938)
+++ ucs-school-lib/python/models/user.py	(Arbeitskopie)
@@ -74,6 +74,11 @@
 		super(User, self).__init__(*args, **kwargs)
 		if self.school_classes is None:
 			self.school_classes = {}
+		if self.schools is None:
+			if self.school:
+				self.schools = [self.school]
+			else:
+				self.schools = []
 
 	@classmethod
 	def shall_create_mail_domain(cls):
Index: ucs-school-umc-wizards/umc/python/schoolwizards/__init__.py
===================================================================
--- ucs-school-umc-wizards/umc/python/schoolwizards/__init__.py	(Revision 72938)
+++ ucs-school-umc-wizards/umc/python/schoolwizards/__init__.py	(Arbeitskopie)
@@ -200,8 +200,13 @@
 			if obj.errors:
 				ret.append({'result' : {'message' : obj.get_error_msg()}})
 				continue
+			obj_loaded = obj.from_dn(obj.dn, obj.school, ldap_user_read)
+			for name, _attr in obj._attributes.iteritems():
+				new_value = getattr(obj, name)
+				if new_value is not None:
+					setattr(obj_loaded, name, new_value)
 			try:
-				obj.modify(ldap_user_write, validate=False)
+				obj_loaded.modify(ldap_user_write, validate=False)
 			except uldapBaseException as exc:
 				ret.append({'result' : {'message' : get_exception_msg(exc)}})
 			else: