UIButton Buy Now effect

Question

Hi.

I want to make a "Buy Now" button in my Application, which should work the same way as the one in the App Store, but I dont know how to resize the UIButton with an animation.

I have tried the following, but it resized the button at once and not as an animation:

[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:10.5];
[buyButton setFrame:CGRectMake(20, 115, 70, 21)];
[UIView commitAnimations];

Where the "buyButton" is a UIButton.

I've checked ou this post http://stackoverflow.com/questions/1669804/uibutton-appstore-buy-button-animation, but is does not seem to work.