IMO, a separate DTD for EAP is even uglier.
DTDs to be created are jboss_6_0.dtd, jboss_5_x_eap.dtd. And in case we want to support this in 5.x non-EAP versions then also jboss_5_x.dtd.
And after that, if we want to have a common setting for both EJB2 and EJB3 we may end-up with a system property anyway.