Are the MATs you are applying for the clothes or for V3? If the MATS are for the clothes, apply them only to the clothes, if they're for V3, make sure you have your clothes conformed first, then apply the MATS to V3. I'm assuming by MAT character you mean a MAT pose. You don't really apply characters to other characters - you either conform or parent them. Maybe you could give us a step by step breakdown of what you're trying to do, and which clothing/poses you're trying to do it with?