So, i am trying the whole afternoon to get a step further, and maybe i did.
Until now i booted my system with
GraphicsEnabler=No. My graphics card (hd5670) was detected as Radeon 5000 series.
When i tried to boot with
GraphicsEnabler=Yes i got a panic in ATI5000Controller.kext. But when i ad
AtiConfig=Hoolock, the system boots up and my card is detected as 5600 series. I tried Langur so far but it ended in a black screen. But i still have glitches and artifacts.
wastez, i think you tried different framebuffers. What was your experience?
Now i'm gonna try some different framebuffers and maybe some other smios.plist. This has to work somehow

.