Changing Camera when Casting Ability

I'm trying to make a setup for some artillery units. I've got the firing set up just fine, but I want to make it so that when a player clicks on the ability to fire it, it will move the camera into an overhead position of the map so that it has a feel similar to a satellite, and then they zoom the camera in and out a little bit while in there.
I can only seem to get it to change the camera AFTER the unit fires the abilities, rather than change the camera while the players choose where to fire the artillery at.
Anyone have any idea how to do this?

A more advanced WE user may have to correct me on this but I believe there is one way. Try make the fire ability a instant cast, and when you click on it does nothing but activates a trigger. Add another ability to the unit (the one with the selection to fire) and order the unit to use it. At the same time change the camera. The effect is that now you have a camera at the same time you have the selection to fire.