That's awesome you got it to work. It would be even more awesome if you uploaded your ATI6000 Kext so others could benefit too.
I would have but never figured out how to upload the kext. I have sold the ATI card anyhow and installed the Zotac Nvidia GT640 Silent graphics card. Works OOB without any drivers or hacks. I am using FCP and handbrake without issue. Works great!