I just added a Skin Material Example to the Vehicle Material wiki page which includes a colorPaletteMap property. You'll have to add this property to your map as well as a corresponding color palette texture which should look like this: This texture define which areas are affected by the first, second and third color picker. Red parts (RBG = 255,0,0) will be affected by the first, green (RBG = 0,255,0) parts by the 2nd and blue (RBG = 0,0,255) parts by the 3rd color picker. The filename of such a color palette texture needs to have a tag at the end which indicates which UV map it should (e.g. sunburst_skin_rally_palette_uv1 is using the second UV map of the object (cause the index starts at 0!)).
