ummmm ok think this is what ur after
just look for the human spell "sphere"
yes then remove the missle art change the "art target" to the short bow model
change the "sprite one" into hand, left (or right) and ur done
But if u want it to be when ur unit gains an item, do the above but make it an item ability and add the ability to the item.
_.-=-._!Kupi's edit!_.-=-._
dw about being more specific not a big deal.