Quite simple trigger. Maybe I'm just completely blind, but it seems there is no way to refer to the Unit constructing the structure (not the constructed unit). "Triggering Unit" does not work.
Edit: My problem is (if I wasn't clear enough): I can't find a way to refer to the Constructing Unit,
Edit: My problem is (if I wasn't clear enough): I can't find a way to refer to the Constructing Unit,