radgridview export to excel skip columns

I have a winform application with several radgridviews.  I have added export functionality, but do not see how to skip a column when exporting.

I did some research but nothing I found specifically shows / code examples of how this can be done in winform.

Here is my code.   

 GridViewSpreadExport spreadExporter = new GridViewSpreadExport(gv);

                spreadExporter.HiddenColumnOption = Telerik.WinControls.UI.Export.HiddenOption.DoNotExport;
                spreadExporter.ExportVisualSettings = true;
                SpreadExportRenderer exportRenderer = new SpreadExportRenderer();

                spreadExporter.RunExport(filename, exportRenderer);

I did try this:

radGridView1.Columns[0].ExcelExportType = Telerik.WinControls.UI.Export.DisplayFormatType.None;

and then calling the above code, but the column still shows up.

Why isn't there a simple property on the column ShowInExport we can set to True/False?

Thanks,

Roger