Perhaps I misunderstood, I thought you were trying to do letter engraving in Bryce. Well, you could always export the terrain as a mesh and then reimport it into Bryce, but that seems a bit silly. The link is to the free gems by HumanoidExotik that I mentioned. If you like rendering jewelry, they may be helpful. I don't know what app they were orignally modelled in, but it sure wasn't Bryce. Though they do import quite nicely. Also, you might want to check out the thread on TIR (further down on the forum page), it's a neat render setting for Bryce when you're working with jewelry and gems that really makes things sparkle.