You will need to get details on MSDN on how to use chart/chartSpace with either js or vbs. It "may" allow what you are trying to do. You would have a -config:configChart.js as part of the logparser params. The configChart.js would contain what you need to have done. An example of this would be:
function setAxisTitle(axisNumber, title) {
var axis = chart.Axes(axisNumber);
axis.HasTitle = true;
axis.Title.Caption = title;
};
// Change the background color
chart.PlotArea.Interior.Color=chartSpace.Constants.chColorNone;
try {
chart.Legend.Position=chartSpace.Constants.chLegendPositionBottom;
}
catch(e) {
}
For what you want you will need to do some digging in MSDN.