Not with JEE6, in fact my EJB works perfectly when I don't use JPA. But it's the JAP persistence.xml file that must have an error... the problem is it doesn't show any information about it, not any log.
And I don't even know for sure if my properties prefix is the correct one for the default Glassfish JPA implementation.
Thank you very much for your replies! Any other idea?
subject: JPA2 and Glassfish: persistence unit not found