I've come across these problems:

1.  If when describing a WebGridColumn if the Name atrribute is not the same as the DataMember when you display the chart it fails with a JavaScript error.  You can see this error in the samples.  Open the VB ChartHeader_Layout sample and change the WebGridColumn Customer ID name to CustomerNum and run sample the chart fails to display (browser is IE 7, Firefox 3.x).

                <ISWebGrid:WebGridColumn Caption="CustomerID" DataMember="CustomerID" Name="CustomerNum"
                    Width="100px">

The Grid displays correctly so it looks like the Chart uses the Name instead of DataMember.

2. Using the sample above (correct the error), the Header does not appear.

3.  Again using the above sample, remove the Order date from the series area to the Category area and add EmployeeID to the Data area.  Now the legend shows as "Series - Count(CustomerID)"  how can you change this text to something else like:  "Total CustomerID"  or Something like "Total <caption>".

Thanks

John