ConvertDataUnitsToPhysical functionality should be able to return results relative to the entire chart, so that a user can place an object over it.

REASON FOR DECLINATION
This is supported out-of-the-box by the new RadChartView.

Having Series Mapping, a specific XCategory needs to be highlighted.

REASON FOR DECLINATION
This is supported out-of-the-box by the new RadChartView (use the LabelTemplateSelector of the axes).