In order to change costumes (NOTE, will have to reconnect after changing):

1. Decide which costume you want.
2. Rename char.ini to something else.
3. Rename char (costumeyouwant).ini to char.ini
4. Rename the emotions folder to something else.
5. Rename the emotion (costumeyouwant) folder to emotion.

And there you go! Next time you connect to a server as that character, they will have the alternate costume!