Ove,
The @StaticMetamodel isn't related to EJB3.1. It's a JPA construct. You might want to ask this question in a JPA specific forums like Hibernate. You have a better chance of getting it answered there, than here.
By the way, I guess you have already come across this http://docs.jboss.org/hibernate/entitymanager/3.5/reference/en/html/metamodel.html