Greg is right about the Rit dye,I did my old blue ones on the Dart look great but had to get 2 boxes, to get the black look,in your case Greg, red to black be ready you may need more than 3 boxes.
I ve been painting plastic trim pieces with Krylon Dual. Goes on nice and seams to be a fairly tough finish.
For belts, check out build thread by AIV. http://www.forabodiesonly.com/mopar/showthread.php?t=254194&page=20 He just did his black belts and they look great!
For the plastic backs clean them really well & use an adhesion promoter. Here's my before & after pics....