Setting Towers To Attack With Abilities (Earthquake)

I know it's possible, I've seen it in a few games and I'm trying to reproduce the effects.

Towers can be created to cast abilities like chain lightning, earthquake, and starfall.

Does anyone know how to setup a tower to use those abilities as a main attack? I got some trigger work done on it but it doens't have all the abilities ie: earthquake.

For earthquake, look under issue an order targeting ground.

Make custom orb abilities, and in the Abilities field choose what you want e.g. earthquake. Then uncheck the 'Item Abilitys' box and give them to the tower.

Give them the earthquake ability and unlimited mana.

E: Unit (attacks a unit, or targets a unit I don't know. Target might now work because they might still be targeting the enemy after they attack thus it would only cast it once)

A: Cast X on targeted unit

(or somethin like that)

or you can just use the random: Prodjekt art thing and go to abilitys and choose the type of ability you whant it to use :infth:

u could also make that when ur tower attack an unit it get forced to cast an ability on that unit.... i know that work with triggerin