Ok, so I am trying to add charges to an ability via a trigger. I have looked at other posts and in other forums and found the general method (i think).
What I have is this:
A shop where you can buy grenades that are used by an ability. The shop has it's own ability called "Buy Grenade". It is basically a dummy ability that I use for the trigger. Every time the "Buy Grenade" ability is used, I want it to add a charge to the "Toss Grenade (Hero)" ability that is on my Raynor. Of course, the end result of this trigger should work for all players, but right now I am trying to make it work for an individual unit, just to debug it. My trigger so far is this:
Unit - Pawn Shop [148.50, 84.50] uses Buy Grenade at Generic1 - Any stage (Ignore shared abilities)
Unit - Add -1.0 charges used for charge "TossGrenadeHero" on ability Raynor - Toss Grenade (Hero) on unit Jim Raynor (Hero) [151.00, 82.17]
Now it isn't working. I know the Event works because I added a move command under the action to test it, and that worked. So something is wrong with the Action. Even if I try to take charges away by making the value 1.0 (instead of negative), it doesn't work. The ability Raynor-Toss Grenade (Hero) was linked in through the pull down menu. I only have one Jim Raynor (Hero) on the map. So it must be something with the "used for charge...." I'm not even sure what exactly I am supposed to put in that category, as it requires a text string as input. The charge link in the ability was set to "Abil/id" and in the map, it changes that to "Abil/TossGrenadeHero". I tried putting all of those for the input, and none of them worked.
You need to enter the complete path, with the Abil/ part. Other than that, it should work the way you describe it. Make sure, you use the correct link; check for typos. Attach the map, if it still doesn't work.