Named Queries for human-task are not compatible with hibernate impl/ for JPA 2.0

Hibernate impl. of JPA 2.0 spec generates extra inner joins on the base of named queries for human tasks. It causes empty results on retrieving task assigned to group.

When I start TasksServer (i.e. Mina) in J2EE environment (EJB 3.1 and JPA 2.0) hiberbate generates 2 extra inner joins in query for group tasks:

inner join OrganizationalEntity user7_ on task0_.actualOwner_id=user7_.id
inner join OrganizationalEntity user8_ on task0_.createdBy_id=user8_.id

So group tasks have empty values in actualOwner_id and createdBy_id columns (because it's group task) and result of this query is always empty.
Problem exist for following queries:
TasksAssignedAsPotentialOwner
TasksAssignedAsPotentialOwnerWithGroups
TasksAssignedAsPotentialOwnerByGroup
SubTasksAssignedAsPotentialOwner

This problem is described here: https://hibernate.onjira.com/browse/HHH-5518

Need to modify named queries in human task