Ok I did what Celdia said in http://ffhacktics.com/smf/index.php?topic=6702.0 but here is the problem. I want if possible not to replace any sprites in unit.bin just put my own in there. How do i do that?
You don't. Luckily, many sprites in UNIT.BIN aren't actually used by the game, and you can use Glain's UW Entries Editor to change which Job the unneeded entries relate to. You can find the UW Entries Editor by either going through my Spreadsheet Shoppe or using the Important Links in the main FFT Hacking section.
thanks i will give it a try