Add ability Metamorphosis problem

I have a custom hero, and a trigger that gives him a custom Metamorphosis spell. but when the trigger gives him the spell, and he uses it, it doesnt work properly... but if i get the hero to learn it normally, then it works.. ?? any help? any way to get around this with triggers?

I believe you want to use Level Up Ability instead of Add Ability. I think that's how hero abilities are given properly.