If you really want to dye the material, you need an acid dye. The actual color is a nylon overlayed on the neoprene. Neoprene itself is just black. You could try a silk dye with vinegar added and a thickening agent to allow it to stay where you apply it, but you'll have to set the dye. I wouldn't reccomend the standard method of ironing, but a pass or two with a steam source might do the trick. The easiest thing to do though would be to buy some nylon in the color you want and glue it on, and don't forget to put a small bead around the edges to keep it from fraying. If your careful, it will look like it was supposed to be there. If your not, pipe a little paint around the edges and say "I meant to do that". People will believe it every time.