xmlns:mx="library://ns.adobe.com/flex/mx" xmlns:s="library://ns.adobe.com/flex/spark">
@namespace mx "library://ns.adobe.com/flex/mx";
mx|Button {
upSkin: Embed(source='a.swf',
symbol='MyUpSkin');
overSkin: Embed(source='a.swf',
symbol='MyOverSkin');
downSkin: Embed(source='a.swf',
symbol='MyDownSkin');
}