How to do a item based trigger spell

I want to do a spell where a unit can click a charged item, then a fireball or some other projectile will shoot in the direction the unit is facing and knock out anyone in front of him.

My original attempt was to give the unit a Demonic Figurine and change the Doom Guard for a shade. The shade then moves up ahead and kills enemy units. The problem was in the events. First I used the the player or unit summons event, but it didn't recognize the summon, probably cause it's a item doing the summoning. Then I tried doing a unit enters the map (the summoned shade), but then I don't know how to make the entreing unit shoot in the direction of the summoner, since this trigger should be used for anybody with the item, not just 1 unit.

My guess would be to do something with orders. I just forgot how to get orders from items. I used to know in the old mpq days, but not to sure how to do it now.

BTW, it has to be a charged "one tap" item. By "one tap" I mean no selecting enemy units, or aoe range, just click.

So any ideas?

I think the event you're looking for is "A item is manipulated" I believe that's the Event you're looking for (might be worded a little different)

*Edit* It's in the Generic Unit Event (Unit category) and it's "A unit uses a item"

I tried this one to, but I couldn't control the summoned unit with that event. I guess I could probably make the item a dummy spell, and creat the unit/projectile that projects from the unit manipulating item.

Uh the "Unit spawns a summon unit" event works fine for me using mechnical critter.

I must of been doing something wrong, spawn does seem to work.

Couldnt you just give it your ability, than get when that abilities being cast?

[edit]Using the Event "Unit- Begins Casting a Ability"