I could be wrong here but I think to do this you need to patch eqgame, or use dll proxying/injection...
Wrath that runs Enlightened: Dark Ascension has done this with UF (maybe ask him?). The download page is here
http://enlighteneddark.weebly.com/downloads.html - the files include the resources needed. IIRC it was still a bit quirky in regards to what you saw at character select for the classes.