Put in more ballista battle animation palettes in FE8?

How would I add more ballista palettes to FE8 for use with battle animation 9F? I have added more ballistae to my game and use animation 9F for them, but only item IDs 35, 36, and 37 (the original GBA ballistae) have palettes in battle, and any other ones ballistae display as either garbage or all black.