How to give an attack a sound?

I want a unit of mine to have a special attack sound. How do i make that happen? And how do i get rid of the sound that is attatched to the projectile graphic im using? Can anyone provide some insights?

For adding the sound triggers do it pretty easily.

Event: Generic unit attacks unit
Action: Play 3d sound (place your sound here) at position of attacking unit.

I can do this in the normal TFT World Editor?
I see no trigger that says unit attacks.. :-/
Theres unit dies unit casts a spell bla bla bla but no unit attacks..
Also how do i select a generic unit and not a specific unit?