[Mangos Three] Spell Arcane Missiles not working... how to fix?

[Corsol]

The spell "Arcane Missiles" (id 5143) need an aura to be activated.

That aura is "Arcane Missiles!" (id 79683) and it will be applied to player correctly. But (and now ther's the problem) the spell will not be activated to be used.

So i've the aura but i can't use the spell.

How to fix this problem?

Thanks