Just convert dds texture into bmp (using DXTBmp), edit it with Gimp, Paint, Corel, Photoshop, or any other program and convert it back into dds. That's all. But yellow cuffs and collars are already in Kochi's skin (they are also in one of my skin, but it has different details on the front of jacket). Ask him whether you can use his work. But don't you think, that you should write your post in a bit different way? Maybe with "please" and "could you"?
Griff, thanks! When I see such posts I really feel that it was worth spending so much time to do this