I need less help on doing it, I mean a tutorial would be great, but could someone make an item.dat file for me that has 512 Textures, Demon Force, and Raider Lax? Thanks.

don't be lazy

replace these lines in item.dat

FORCOL 0; 0 30 1 30 2 30 3 30 4 30 5 30 6 30 7 30 8 30 9 30 10 30 11 30 12 30 13 30 14 30 15 30 16 30 17 30 18 30 19 30 20 0
RELCOL 0; 0 106 1 106 2 106 3 106 4 106 5 106 6 106 7 106 8 106 9 106 10 106 11 106 12 106 13 106 14 106 15 106 16 106 17 106 18 106 19 106 20 0
REPCOL 0; 0 30 1 30 2 30 3 30 4 30 5 30 6 30 7 30 8 30 9 30 10 30 11 30 12 30 13 30 14 30 15 30 16 30 17 30 18 30 19 30 20 0

TEXBODY 0; 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0

for the 512x512 textures you have to put the .pngs of appropriate size into the folder of the player you're editing