Ball dangling on string

Hey all,
I’m working on a flash site and want to have it start off with a ball attached to a string dropping from the top of the screen. I’ve gotten gravity and bouncing balls and the physic behind those down thanks in large part to this great tutorial:

I have no clue where to start though as far as having an elastic string attached on one end to a fixed point at the top of the movieclip and on the other end to the ball. Does anybody have any tips, ideas, places to start, etc?