How would you add a costume to Mewtwo?

[U-Throw]

I'm new to texture hacking, and I've created my first texture, complete with a Battle Portrait, CSP and Stock Icon. So, if I understand the way costumes work correctly, each character has 10 costume slots, and Mewtwo uses 8 of those 10. So, I think I'm able to add a costume to him. However, I'm not exactly sure how to. I would think I would name the model FitMewtwo008.pac/pcs, but how would you get the Battle Portrait, CSP and Stock Icon to match up with the model? I'm really sorry for taking up your time.

 

[Narpas_sword]

Sticky topic bud:
http://smashboards.com/threads/a-guide-to-replacing-costumes-for-3-5.383614/#post-18440268