Hey Nocturn,
I don't think a fabric paint would work. The only other suggestion would be to try spray paint. The Fabric paint is rather thick.
I don't know I'm at a loss on this one.
But after going to FIDM and seeing the Fett on display first hand, I'd say tan.
Take a look at the photo in this thread.
http://www.thedentedhelmet.com/showthread.php?t=11166
I think Darth Mule is confusing ROTJ with ESB.
I'm doing an ESB and I know its grey.
If you have any other ?'s lmk.
Christi
P.S. Did you try a color remover?