Well, the easiest method (and the only one I know of) with UV Mapper is to remap the character to match the layout of the texture you want to use. Obviously you won't be able to do that with all characters, as some have more parts than others. For instance, it would be very difficult to remap my simple dragon model to use the MilDragon's textures, because the MilDragon has more parts, and a more complicated map than mine does.