Those were not the final buttons -- the article and that demo page note that the final buttons are only visible in production, the last demo doesn't work in IE and has pretty heinous markup.
Sorry, incase it was not obvious meant the final buttons in the article not the ones they actually use in production (which he says you have to reverse engineer yourself) as per his comment http://stopdesign.com/archive/2009/02/04/recreating-the-butt...