But I'm still having problems with my distance blur [...] effect because the DepthMap doesn't work correctly for sky-entitys.
What exactly doesn't work? I am not sure what is written into the depthmap (is it 0, maybe?), but since camera.clip_near should be > 0, I would overwrite all pixel depths below camera.clip_near and beyond camera.clip_far with the value of camera.clip_far.
