/**
 * @author Alexander Farkas
 * v. 1.02
 */
(function( $ ) {
	$.extend($.fx.step, {
		backgroundPosition: function( fx ) {
			if ( fx.state === 0 && typeof fx.end == 'string' ) {
				var start = $.curCSS(fx.elem, 'backgroundPosition');
				start = toArray(start);
				fx.start = [start[0],start[2]];
				var end = toArray(fx.end);
				fx.end = [end[0],end[2]];
				fx.unit = [end[1],end[3]];
			}
			var nowPosX = [];
			nowPosX[0] = ((fx.end[0] - fx.start[0]) * fx.pos) + fx.start[0] + fx.unit[0];
			nowPosX[1] = ((fx.end[1] - fx.start[1]) * fx.pos) + fx.start[1] + fx.unit[1];
			fx.elem.style.backgroundPosition = nowPosX[0] + ' ' + nowPosX[1];

			function toArray( strg ) {
				strg = strg.replace(/left|top/g, '0px');
				strg = strg.replace(/right|bottom/g, '100%');
				strg = strg.replace(/([0-9\.]+)(\s|\)|$)/g, "$1px$2");
				var res = strg.match(/(-?[0-9\.]+)(px|\%|em|pt)\s(-?[0-9\.]+)(px|\%|em|pt)/);
				return [parseFloat(res[1], 10),res[2],parseFloat(res[3], 10),res[4]];
			}
		}
	});
})(jQuery);ø