Advanced Shape Tweening

I'm doing an animation, which shows a signature being signed. Sort of the way you would see something being written. It's pretty easy to do with key frame animation, but I was wondering if there is another way to do this with actionscript or a shape tween, just because the file size gets pretty large with the keyframe animation style.

Also, if this isn't possible, please let me know that too, so I don't want two weeks working on this.

Could you describe what you want to show exactly? I understand the animation, but are you trying to animate a hand/pen signing or what?

Correct, I am trying to animate a hand/pen signing.

Well it makes the most sense to have your 'signature' overlayed with a motion guide, and then have the pen follow that guide. Actually I found this which might be more helpful than me.

http://originalflash.com/tut_signature.html

There are ways to do it with Actionscript, but this seems simpler.