compiz and viewport switcher

[stan]

I'm using compiz on some machines at work, and have set up the "rotate
desktop" feature so that I can change workspaces with my mouse's
scroll wheel. I tried doing the same on a machine at home, but I don't seem
to have an option in the advanced desktop setup to allow "viewport
switcher" which seems to be required to make this work.

could this be a function not supported by the video card I have at home?

-- 
One of the main causes of the fall of the roman empire was that, lacking
zero, they had no way to indicate successful termination of their C
programs.