not sure that this would work, since the Cube6 uses map6 properties, ie
a single image wrapped around all the faces.
try using a bit map like the skyBox example and change the colours on
the surface that you want to change, that way you can have some control
over the individual faces..
also you can always swap bitmaps at runtime so you can change teh
material colors by swapping bitmapmaterials
hope this helps.
Pierre