I don't know much about casting or stabilization but i guess they're both done the same way in a pressure pot. I have 4 pieces of Bog Oak Burl i need stabilized.
Best bet, if you care about it and aren't planning on doing it a lot yourself, is to find a commercial service that will do it for you. One is mentioned here quite often, but I forget who it is. I believe they charge by the weight of the pieces as they leave after stabilizing...