I've not actually used it, but I'm pretty sure it is as they have examples of it. See http://docs.jboss.org/ejb3/app-server/tutorial/tableperinheritance/
Have you tried specifying a generation strategy for the keys(ids) perhaps Table?
This is an inherent limitation of TABLE_PER_CLASS, you cannot use IDENTITY as a strategy, either use SEQUENCE, TABLE or a hibernate specific generation strategy
Thanks. using TABLE solved my problem.