How do I set up the RangeSelection to do this please?

For a standard horizontal x-axis, I use:

NRangeSelection rangeSelection = new NRangeSelection
{
HorizontalAscendingZoom = true,
ZoomOutResetsAxis = true,
HorizontalAxisId = (int) StandardAxis.PrimaryX,
VerticalAxisId = (int) StandardAxis.PrimaryY
};
chart.RangeSelections.Add(rangeSelection);

If I set
chart.SetPredefinedChartStyle(PredefinedChartStyle.HorizontalLeft);

What do I change the rangeSelection to? I've tried various permutations, but none of them allow me to zoom. I get a red rectangle dragging the selection area in all directions.

Thanks

Kevin