Currently ldm only launches a desktop session through the Xsession script if you let it use the default desktop. If you manually pick a different session (like /usr/bin/gnome-session) it will run it directly, bypassing important stuff that happens in /etc/X11/xinit/xinitrc.d. ldm must learn how to run all sessions through Xsession.
Changing version to '9' as part of upcoming Fedora 9 GA. More information and reason for this action is here: http://fedoraproject.org/wiki/BugZappers/HouseKeeping
This was fixed a long time ago