I am trying to make a realistic candle but I'm having no luck with the flame. The candle is modeled in Rhino (left) and rendered in Bryce. When I set the flame as a volume, "voluminous fire" (right), it doesn't show up. I can set it to the volume "purple brain cloud" (center), and it looks fine...but don't want a puffy, purple flame.

It is surely something simple, but what am I doing wrong?

thanks