M I thought it didnt matter where you put an ambient light as it lights all things in the scene equally regardless of occlusion? I mite be wrong but I think that's what it does.

Roach105 go with what M said use ansiotropic and not full black, you can then adjust the specular highlights to get some interesting effects (Sorry we just covered ansiotropic lighting models in a lecture and now i think they're kinda cool)