That format option is only for values I think. Anything after the format string will show as text on the chart. You have to use "series x point colors" under the section "series colors" section. I didn't find it too flexible too to change the text and background colors etc. but worth a try.
Thanks for the suggestion. We have tried your suggestion, but what it does is that we get a black background when we select Black and white letters. We actually want white background and black values. We have tried white but than you do not see anything. It looks like I can not control the font color of the label text. Do you have another suggestion?
