The Apex statement of direction mentions for the 4.0 version a j2ee Apex listener, as an alternative for mod/plsql, and additional Authentication schemes.
Knowing that R12 doesn't support anymore mod plsql, i read in the tea leaves that the 4.0 release will add an Apps EBS Authentication scheme connecting via the new listener.
In the mean time, some more posts will follow that describe how we integrated Apex with Oracle's eBusiness suite.
