Flex :: Add Icons To A PopUpMenuButton Using A XML File?

I've been looking at the following example for populating a PupUpMenuButton [URL] and would like to add icons to each menu. Ideally, I would specify the icon in the xml and assign it in a similar way to using labelFunction for the text. The only information I've found via google is to create a menu as follows

(seems I can't include more than one url, but it is an example that creates a menu object using the following function):

private function initMenu():void {
menu = new Menu();
menu.dataProvider = xmlList;
menu.labelField = "@label";
menu.iconField = "@icon";
}

but I would really prefer to build it all from the XML file.