In gdm.conf-custom

0=Xgl

[server-Xgl]
name=Xgl server
command=/usr/bin/Xgl :0 -fullscreen -ac -accel glx:pbuffer -accel xv:fbo -kb
flexible=true



In /usr/bin/startcompiz

#!/bin/sh
cgwd &
compiz --replace gconf &


In session startup:

/usr/bin/startcompiz &