Goto FSF. Open up Calculator, choose scientific mode and choose Hex. Type "2D0" and click dec. That number you put into FSF where "needed bytes are". Click search beginning of rom. Than turn that 16 number into 1. Hit search. That offset will be used in UNLZ. Write to rom, check the pointers box, and insert the new offset into the image area. Click ok and it should work.
I never tested this with a Pokemon before, but I did it with the into sprite of the hero. I don't see how it'd be any different.
And by the way, when it auto aborts...DO NOT CLICK OK, click CANCEL.