Ordering spellbook spells with triggers

I tried using search but I couldn't find anything on this, so how do I order a unit to use a spell from the spellbook? I tried just using the order string but that didn't seem to work.

i think Force UI will work

Do Force UI key <spellbook hotkey>
then
Do Force UI Key <spell hotkey>

else just have them use the spell book then order the string of the spell in the book.

Although this doesn't seem to work, I found an alternative solution of hiding my spell (enable/disable).