most of them skins only get moded for the game, any outside editing of the skins can get one banned from novaworld.com stats servers real fast.
a host can use a mod that has new skins made and all using them in a server hosted by a gamer. players and host have to have the same skin. this is call even fair game balance. player and host use anything in the mod.
to change the skin for any charters to they not look the same is to some a cheat do to somthing was change about it. this is why some can get banned for this reason.
if you like to make skin for charters to use in a mod and all can use the same skin this is cool.
to edited the skin go here they know the in's and out's when it come to making skins and mods for the games
1.)
http://www.dfarena.com/
talk to them in their forum, terranova
main site for thier mods:
http://www.terranova-exp.com/