You must either use the Omega drivers or use a fix for the normal Catalyst drivers that will modify the code. My laptop also has the 7500 mobile. I use the Omega's myself.
To make the Catalysts work, use a Mobile Mod tool (they just replace a few lines of the driver text file):
Rage3D's MobileMod is here:
http://www.rage3d.com/board/showthre...eadid=33717450
Or
DriverHeaven.net's Mobility Modder:
http://www.driverheaven.net/patje/
rob