I'm not sure how you could get it to combine two spells... maybe with the "useweapon" command, but I'm not sure...
Psionic storm is considered a weapon, so in the templar's spell casting animation, you could put a line saying "useweapon [weaponid]" and see if that works.
I'll go test that, and I'll come back and tell you how it goes.
ADDITION:
OK, I got it to work... sort of. The problem is, in my method, the Templar will ALWAYS cast an additional spell, no matter what it casts.
Here's what I mean. I gave the Defiler a command to cast Psi Storm during it's spellcasting animation. The problem with this is of course, whether it casts Plauge, Consume or Dark Swarm, it will ALWAYS cast Psi Storm as well. There may be a way around it, by giving it a command that only casts Psi Storm if the target is not at a certain range.
If you want to do it this way, go ahead. I'm sure one of those scripting wizards (Bob, BST, SD, etc.) will come up with a better way.
Open up Arsenal III's weapon editor, find the spell (all spells are under Other Weapons). Copy down the weapon ID number (bottom right). Then, use IceCC and open up the unit in question's script.
In the spell casting animation, add this command:
useweapon x (where x = the weaponID number.)
Sorry I couldn't come up with a better way.
