Ive had some success doing this but i have now stumbled across 2 problems. First of all i tried turning a downloaded Vader into a Desann (without changing desann at all). I added a section in the npc's file (assets0/ext_data/npc's). I copied desanns entire section, added vader at the end of Desanns name and changed the player model name to the file vaders stuff was in. I zipped it all into a pk3 and I could spawn the Vader, but he had a blaster (that he wasn't even holding properly) and didn't use the force, except for when i tried to grip him at wich point he pushed me aside just like Desann would. My second problem came when i tried to change a yoda into a npc. I got it fine and used a jedi trainer section of the npc list. I even got him scaled right, but when I spawn him his lightsaber seems to start in his stomach and comes out of his head. If anyone can help me, please reply here or send to [email]email@example.com[/email]:D
you have to set his name (npc name and folder he's in) into reborn_yourskin . thgen he will ahve dark force powers and a red lightsaber. you may have to restart the entire campaign, don't know. that doesn't mean he'll speak like a reborn, tha's just the mark: aah, that one's supposed to be a dark-sider-lightsaber-swinger, got it?
I'm not sure about Vader, I think you need to change something in scripts or some other file, I don't know. Osiris made a jedimaster mod, and he turned jan into a jedi but I'm not sure how. As for the Yoda, every time you change character, you have to restart the game, you can't load the game.