<A target="_blank" href="http://www.bleedyellow.com/blogs/uhclem/entry/how_to_install_2_versions_of_the_same_app_on_a_bes_server4">Chris Mobley offers a way of doubling up</A> applications on your BlackBerry Enterprise Server. This is only, kinda, sorta supported by RIM, though Chris provides a link to their KB article.