When she gets fearful, you can make her sit and put on a happy tone of voice...oh you silly dog, nothing to be scared of...good sit...don't make a big deal, just tell her how silly she is and ignore it. As she comes to trust you, she'll learn to follow your lead in how to react to things too.
I think you should call the HS and tell them that this trainer is WAY off base in her knowlege of handling fearful dogs! That was ridiculously bad advice. There is definitely a place for prong collars with SOME dogs in SOME situations. Fear/fear aggressiveness is never one of those situations though.
Cooper The WonderDog
Daphne The Destructo-Rott