11.1 beta - compiz broken?

I have just installed the Gnome desktop from the beta1 DVD, Nvdia’s latest beta driver (177.76, required for my Macbook pro), 3d accel and the desktop in general is running fine. The problem is when I add “composite” “on” in xorg.conf - compiz-manager seems to load, all Metacity (it’s Metacity, right?) window decorations are gone, but compizconfig segfaults, and I cannot set any effects. This leaves me stuck with no window titlebars, and no possibility to even switch applications (alt-tab). Any hints on what went wrong?
Thank you