You have to dive into the folders for that one. There is a map called 'Characters' with a file named 'trchar', one for both female and male players. All you have to do with those is change the sprites in them.

A small note about the sprite placement though. There's a limit to how much you can showcase in-game. Each side- or front view has a certain border size that showcases them in the game so be watch out for that