Here are the steps i did.
1) Got 10.8.1 on usb :/ should work wiht 10.8.2 as people claim. (using beast.)
2) removed graphic card and other unnecessary usb stuff
3) boot into usb (no parameters added)
4) format hdd to GPT installed mac. Reboot. Leave Usb inside.
5) login to mac get #####
6) selected my settings. as well as placed my copy of the DSDT (does not contain any graphic card stuff), mosty for sleep and audio and internal graphic card etc.
7) using kbeast installed the 3 Kexts and rebooted computer. The ocmputer should boot up fine.
8) turn comp off. addd 6950 leave wire connected on internal graphic card (might wana leave bios to boot from internal graphic card too)
9) boot into mac using internal graphic card. swap wire into 6950
10) blue screen. dont do anything just restart. u wont see boot screen or anything depending on ur Bios (if onboard is set as primary graphic or its auto..)
11) u wont see any screen until booted into mac. at this point u have 6950 full supported.
if you restart mac u wont have any problem booting into 6950 without onboard swap. but if u turn off, you will hae to repeat. onboard.. -> boot -> swap. -> blue screen -> restart. and ur good again.