On a side note you can also use a color layer above it and use the alpha matte to knock out the color. ie press f4 change track matte to alpha or alpha inverted. your possibilies are endless this way as you can use solids, gradients or any other layer to go off of.
Hope this helps.
P.S. I have this same set, it rocks
Director/Producer
Kearney Media
Kearney, NE
http://www.kearneymedia.net
“Film in Nebraska, where the men are men and the sheep are pants” – NE Film Commision