Light is not cast on own craft

Light from lights on the craft can be occluded by other parts of the craft, but do not actually cast that light onto the parts themselves.
In this example, I put wing inspection lights on my aircraft. I fiddled with the light part for a while, trying different angles, intensities, ranges, etc. but determined that the light was being cast just fine on the terrain that wasn't obscured by the wing, but the wing itself simply was not reflecting the light cast on it, thereby completely defeating the point of wing inspection lights.