Animations should be done through actors. You would create a new actor of type model and set its parent to one shot animation (not the exact name). You would set the model of the actor to whatever animation you want. Create a new event for the actor and set it to Effect.EffectName.Start or Ability.AbilName.TargetStart (the last option is up to you and when you want to have the animation play in the ability sequence). Then have the action for the event be Create.
I'm going to leave out parts about changing where the effect happens (with this setup it will happen at the caster). Also for your purposes your model should probably be the photon cannon missile model (not sure of the name).
None.