Auto-cast replaced spell

[k3ronid]

I have a unit for which I change the repair spell to the same but faster one. The problem is that when you change the autocast, it falls off. Is it possible to make some kind of trigger that will immediately put it on autocast when adding a spell?
Skill replacement looks like this:

 

[A]mun]

Should work with:
Unit - Order (Picked unit) to Human Peasant - Activate Repair.
It's under Unit - issue order with no target.