Assuming that your GeForce is AGP and your ATI AIW is PCI, it might work.
Don't know if your Twinview card will allow another PCI GPU at the same time. I say this because ATI Dualhead cards don't allow another GPu at the same time. You may want to check that out on their FAQ sheet.
Don't forget, in order for the ATI AIW multimedia properties to function, it must be set as the primary GPU in the BIOS.
Please post if/when you try the configuration.