Hmm, yes, reflections are a big problem. It's lucky you thought of testing for that. I wonder if using a large emissive (and no light) could be a solution. And maybe the strength could be translated as emissive. (Don't mind me, I'm just thinking aloud. 
)
I'll make some tests in pov-ray. (I think it's important for me to understand what's going on in pov-ray before trying to tackle it in Wings) Though, no doubt, you'll have got the solution before that.
For some time, I got sidetracked into reading some of puzzledpaul's quite wonderful problem-solving tutorials. They're not only wonderful examples of lateral-thinking, but encourage you to think, "What if?" I love them
Edit: A thought: why not ask for suggestions in the Pov-ray forum?
Edit2: Just digested your last part, about media. I never used media, but you may have hit the nail on the head. (Slight doubts about reflection, still.)
)I'll make some tests in pov-ray. (I think it's important for me to understand what's going on in pov-ray before trying to tackle it in Wings) Though, no doubt, you'll have got the solution before that.
For some time, I got sidetracked into reading some of puzzledpaul's quite wonderful problem-solving tutorials. They're not only wonderful examples of lateral-thinking, but encourage you to think, "What if?" I love them
Edit: A thought: why not ask for suggestions in the Pov-ray forum?
Edit2: Just digested your last part, about media. I never used media, but you may have hit the nail on the head. (Slight doubts about reflection, still.)