Leveling abilities inside a Spellbook

[Carty]

Anybody know how to do this? :/

I have an ability called "smithing" inside a general abilities spellbook and I want to be able to level the smithing ability with a trigger but I don't know how to if it is inside a spellbook...

 

[Marcelo Hossomi]

You can level an ability inside a spellbook as if the hero/unit had it as his ability