With the normal way to start Compiz on startup I couldn't get the desktop to load properly without login and out, some times more than once.[ie. no panels, panels covering the whole destop, and only the wallpaper, to name a few.]
To get Compiz to load at startup in Maya-Xfce I had to, in Sessions and Startup create an entry for the Fusion-icon with the command line: fusion-icon, only then set up the desktop manager and windows decorator from it.
After a few reboots just to test that it's working, everything is working 5X5 now.
Only thing I can think is, some conflict while loading the desktop. Loading with fusion-icon and not compiz --replace delays Compiz long enough not to cause a loading problem.
I though this info might be helpful