After hours of fixes, I found out that I had to apply the width to the Button element in order to work for IE, but that breaks everything in FF/Safari.
Well I am short on time, I have this markup everywhere in my application.
Kesav Here's one way to (almost) do it. I have to admit that there isn't a semantically correct way to style buttons, but empty elements are never the way to go. I'd still like to argue that using two images is enough - with or without the rounded corners.