Could you post the HF for the whole map, separately?
I know one problem many people have with this type of technique is knowing what a hf should look like
Another thing to try is to run it through Bryce again, but use the initially rendered map (with mountains) as the image map, and the exact same lighting, etc. This will "reinforce" the lighting effect in the mountain area.
Also, any luck on changing the camera settings? I know Bryce is very powerful, so this should be possible.... And it is MUCH easier than POVRay to use, as everything in POV is based on text script files...no modeler/visual designer included.