Bryce will not "bounce" or "bend" light sources through or off of materials. You cannot, for instance, shine a light from the ceiling, onto a mirror, bounce off, and have it illuminate the floor. The floor will remain unlit. Try it sometime. That effect would be simpler than the effect you are trying to achieve, and yet Bryce can't even do that. In order to do this, Bryce would have to consider every possible surface in the scene as a light source, and check each to see if it is reflective, a light is shining on it, and that light would bounce to the surface in the pixel currently rendering. It's totally possible, but would slow down the raytracer tremendously and so is not a feature. To get these types of effects, you must fake it as BT suggests above.