如何在highcharts用addPlotLine在動態更新的圖表(type: 'datetime') ?

目前找不到解法，只有類別可以><

/*
        chart.xAxis[0].addPlotLine({
                value: Date.UTC(2014,02,08 ,05,39,39 ,0),
                color: 'red',
                width: 2,
                id: 'plot-line-1'
            });
*/

http://jsfiddle.net/gh/get/jquery/1.7.2/highslide-software/highcharts.com/tree/master/samples/highcharts/members/axis-addplotline/