u could be lazy and spawn the hammer item, go thru a single animation fo the hammerswing. then make it disapear. the problem (and blessing) of spawning items in the same action they were spawned is that they cant have any weapon collisions. ull have to make ur own hitboxes for that move.
I don't know any of his hammer animations tho, so it probably will be the swing animation instead of the hammer to ground impact animation from wind waker, then again, if I can find an animation that does that, I can just add a hammer to it =D