Would you plz clear for me: Object Relation Mapping is disallower, or exactly Hibernate? If only Hibernate, you should find another persistence provider (toplink or something) and probably fix some mappings. Otherwise, I guess, you better look for another BPM.
ORM is disallowed. iBatis (for stored procedures) might be allowed, but is questionable. Most likely it will need to be straight JDBC with sprocs.