I'm not sure I understood your doubt. Do you mean you have more than one application and want one UsersRolesLoginModule for each one?
yes. I actually solved it already. The problem was a valid entry of a session bean in the jboss.xml. However, the classes where missing. Strangely, jboss then did not handle the security right, even though the bean was not used anywhere. You can try it yourself. Just make an entry to your jboss.xml and add a session bean. You dont need classes or anything for the bean. Then deploy it. Now jboss will not accept additional UsersRolesLoginModule sections. Dont ask me why.