Not sure if there are any Media Studio Pro users here or not, but figured I'd post this just in case there are any around.

I've written a few filters for MSP that add advanced compositing techniques for bluescreen/greenscreen work including a Color Difference Keyer and a despill operation. These techniques are the same calculations found in many dedicated compositing programs.

The download, instructions and a tutorial are available on this web page (http://www.jushhome.com/nick/Tutorial/MSPColorDiff.asp).
Have fun.

[EDIT: SERVER UP AND RUNNING AGAIN
For anyone that had trouble getting to the site earlier, go ahead and try again. The server is back up and running.
Have fun.
/EDIT]