Adding Audio to Movie Clip Button

I am wondering how to add a sound to an animated movie clip button that only plays once. With the code that I am using when you mouseOver it plays the sound and animation, then when you move your mouse off it plays backward and when it hits frame one it plays the sound again. Thanks in advance.


onClipEvent (enterFrame) {
    if (this.hitTest(_root._xmouse, _root._ymouse, true)) {
    } else {