Pie Chart CCC2 and percentage value

Hi,
I'm using this extension point in pie chart in CCC1: pieLabel_text: function(d){ return (d / render_Graph7.chart.pieChartPanel.sum*100).toFixed(2) + "%"; }
If I switch to compatVersion2, there is result NaN%.
Any idea, how to get it working. I didn't change output format therefore it should work.

Thanks a lot,
best regards,
timfu83