Animating a symbol?

Hi there, I have Flash version 8. I'm doing a little attract video for a kiosk. On this one page, there is a finger pointing saying "touch the screen". From the outstretched finger, I want a circle to fade from white to the background color to kind of indicate the finger tapped the screen.

I've found tutorials that show how to fade a graphic symbol on the stage, but that isn't what I want. What I want is to set up a symbol (a movie clip?) to be looping through this little animation of the circle fading to the bg color behind the finger. Then I want to place that symbol onto the stage where I want it to happen. Am I going about this the wrong way?

Can I not do such a fade in a symbol? I have it set as a graphic. Seems when I add the keyframe in the symbol, change the tint, then add the motion tween only the keyframe frame changes, there is no tween.

This may not make much sense, so I have uploaded a simple .fla file to show what I am trying to do. You can grab it here:

http://www.pixelmech.com/rev/touchpoint.zip

Can anyone suggest how I can actually accomplish this fade?

Thanks

Tom