In short.. There is none.
In long.. I can't be bothered coz I would have to make a huge song and dance about it lol. You basically have to figure out which character you want to modify, find out his heirachy set of files.
Extract them.
Just say you wanted to swap them with a deformable mesh, (well you can't make them deformable so...) you then have to cut up your model into corresponding pieces. I.e toe, heel, lower leg, upper leg, etc.. then using kimera you have to swap each of the pieces over, not to mention converting textures to work properly can be a major pain in the ass. Say your doing cloud, I tihnk his first texture starts at rtad, now i cant remember what part his body parts start at but lets just say it's rtai.
So you can only have 6 textures for his body and all of his weapons, if you wanted to replace them all. So you have to sort of squish as many texture files as you can onto one bitmap, which is hard because that means you have to re-texture map all the corresponding models so you have enough texture space to do his body and all the weapons you want to texture.
Then theres the converting proccess.
When in Pcreator you have to open each individual piece of his body your going to swap over, apply the texture flip the mapping accordingly, get the size right, then set the texture number. i.e rtad=0 rtae=1 rtaf=2 rtag=3 etc.
Then theres the fact that you have to properly align each piece of his body on the skeleton correctly so that when its animated you don't have random parts flying everywhere...
Now I remember why I stopped doing this...