Final Fantasy Hacktics

I've been looking around for ages for a method to get characters like Gaffgarion, Zalbag, Dycedarg and more into my party for this game, yet I can't find any. I have emulations for both the PSX and PSP versions, and it would be a nice way to start up a new game to freshen things up, as I'm almost done with my play through on my PSP hard copy of the game.  (Should be noted that I would much prefer to hack the WotL version since it has more content)