onMotionFinished Trouble

Okay, Ive got a slideshow and for the slideshow counter I’ve decided to use a bar and tween classes to make it look nicer. I want it to grow slowly, then when it finishes switch the image, then shoot back and start again… Currently I have

var slideCounter:Tween = new Tween(slideBar, "_width", Regular.easeIn, 0, 640, 5, true);
slideCounter.onMotionFinished = function() {
    if (slideBar<=0) {
        this.continueTo(640, 5);
    } else {
        this.continueTo(0, 1.5);
    }
};

Now I’m begining to understand that onMotionFinished will only work only from the tweens position… It goes back but doesn’t restart itself again?

Anyone with any suggestions?

Dave