there's a tutorial about this exact subject in this months 3d world magazine. I didn't read it but I did see it in there. See if you can get a hold of that magazine and it will tell you exactly how to do it.
But if it were me doing it I would do pretty much what umbrella said you wont be able to "shape" them as far as I know, but if they are small enough it shouldn't matter.
Alan
Technical Director - Framestore
Currently working on: Your Highness
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