Hi Rich,
By default the control will export the element/atom pair as id attribute in SVG. You can however inject any attribute name/value pair inside the generated SVG using the interactivity style - for example:
NChart chart = nChartControl1.Charts[0];
NBarSeries bar = new NBarSeries();
NInteractivityStyle interactivityStyle = new NInteractivityStyle();
interactivityStyle.CustomMapAreaAttribute.JScriptAttribute = "AttributeName='bar'";
bar.Values.Add(10);
bar.InteractivityStyles.Add(0, interactivityStyle);
bar.Values.Add(20);
bar.Values.Add(30);
chart.Series.Add(bar);
NSvgImageFormat svgImageFormat = new NSvgImageFormat();
svgImageFormat.EnableInteractivity = true;
nChartControl1.ImageExporter.SaveToFile("c:\\temp\\test.svg", svgImageFormat);
In the above example all svg export that is associated with the first bar will have a custom attribute. Hope this helps - let us know if you meet any problems or have any questions.