Hi,I am making a mission for FSX and I need to know how to either program ATC what to say and when or how to disable the use of ATC and just use sound clips. Which is the better way to go and how would I do it?Thanks!

I don't think you can "program" what ATC says. In missions ATC works the same as in Free Flight. If that is acceptable, it would save the effort of making several recordings and placing triggers for them. If you need "special interaction" with ATC, I think you need your own recordings.