Casting Custom abilities from middle man?!

This is my trigger so far.

Kill boss ability femur
Events
Player - Player 3 (Teal) Selects a unit
Conditions
((Unit-type of (Triggering unit)) Equal to Ability_FemurDisloacation) and (Hero_CanAttack Equal to True)
Actions
Set Hero_CastUnit = (Triggering unit)
Unit - Add Femur Dislocation to Hero_CastUnit
Unit - Order Hero_CastUnit to Attack Boss_Unit
Unit - Hide Hero_CastUnit
Selection - Clear selection for Player 3 (Teal)

Now... instead of "Unit - Order Hero_CastUnit to Attack Boss_Unit" I want it to say cast's "Femur Dislocation" on boss_unit but when I go into casts... it has all the default casts for the original game...

Order it to cast the spell that "Femur Dislocation" is based on.

It's not based on any of the default spells.
It's a custom spell.

I think he means he .slk edited. Just use whatever order code you used in your .slk editing.

OK, I never SLK edited, so I wouldn't know. Thanks.