First of all: Be CAREFUL with "compiz --replace"
(and) Selecting metacity then back to compiz with the Fusion Icon gives the same result as this:
[ Here's a temporary solution:
Start the Compiz Fusion Icon from System/Administration.
The (blue) icon is displayed to the right on the upper taskbar, to the left of the network icon.
Right-click it (The Compiz of course).
Choose [Select Window Decorator]
Now - the GTK Window Decorator is already marked. So choose the other (Emerald).
Ok. You'll loose the current theme, but you do get the buttons. That is, until some MetaCity idiot makes up for his/her fault and fixes the bug.
Hope this'll help.]