Thats easy, first set the real spellbook's base order ID to somthing like
acidbomb with the minimum and maximum spells set to
11. I'll call that spellbook
SpellBook 1. Then, create a spellbook with the spell you want added into
SpellBook 1 inside of it, with it's minimum and maximum spells set to
11 and it's base order ID to
acidbomb. I'll call that
SpellBook 2. Next, in the initilization trigger, disable
SpellBook 2. Next, give the unit you want to have a spellbook
SpellBook 1. Finally, when you want to add the spells, simply in a trigger use this:
-
Unit - SpellBook 2 to (Your unit)
I hope this helps.