Optimizing shadow volumes

Hi I''ve basically ripped the "Shadow Volume" sample from the SDK (8.1) and implimented it in my game. I''ve got a basic Idea of what it does. Here''s the problem: The shadow volume calculations and rendering takes up A LOT of the renderingtime. Is there any way of optimizing using this technique? I''ve tried reusing volumes for stuff that don''t move (all buildings using same rotation) and right now I''ve build one model without any details (for the shadow) and one real for rendering. It works great but I''s a pain to make the models since it''s hard to make changes to the vertices that''s also a part of the shadow-model. I''ve seen games that use "black fuzz" as a shadow? How is this done? that would work good enough for me (I think). Is there any other tricks for optimizing the shadow volume techique? .Pangplast Screenshos of "Humanoid invasion": http://humanoid.vaultcity.org/