flash actionscript: I am trying to use the functions the easing folder.

I have a ball (ball), which is a movie clip.
I have a button (pinkbutton), which is a Symbol.

Currently, when the user clicks the pink button, the ball will bounce. I would
now like the ball to bounce when the page loads, without the user having to
click a button (I am doing away with the button.) This is what I have now:

pinkbutton.onPress = function()
{
new Tween(ball, "_x", Bounce.easeOut, -100, orgX, 1, true);
}

The ball does the bounce effect when the button is clicked. I want it to
bounce when the page loads.


I tried:

ball.onLoad = function()
{
new Tween(ball, "_x", Bounce.easeOut, -100, orgX, 1, true);
}

and all of the Onloads that are for movie clips, but none worked.

I am just learning actionscript (as you can probably tell by my question).
What can I try instead?

Thanks.