When targeted with ability, do:

I realy hate to ask, but for the life of me I cant figure out how to do this.
I have a abillity, with no damage, no requirements. (Not to give away anny clues about the map I am making) lets call it "tap on shulder"

And I want that when this abillity is cast, on a specific unit type an action is done. I have tried lots of things but cant get it to work, anny ideas?

I'm not sure if you can specify a unit type but heres an example of selecting the targeted unit.

create a unit variable named xxxTarget

E- a unit issues order targeting an object
C- unit type of issued order equals to () <---- insert your casting type of unit
C- issued order equals to order() <--- this depends on orderstring of the spell ability
A- set xxxTarget = target unit of issued order

E- a unit begins casting an ability
C- ability being cast equals to ()
A- create sfx on xxxTarget blah blah <---- or whatever you want

Thank you, come to think of it that was kind of obvius, but alas, thanks.