The SeriesCreated event of the RadChartView's SeriesProvicer is never called when the SeriesDescriptorSelector property is used.
To work this around, you can create a custom chart series descriptor and override its CreateInstanceCore method.
public class CustomScatterSeriesDescriptor : ScatterSeriesDescriptor
{
protected override ChartSeries CreateInstanceCore(object context)
{
var series = (ScatterSeries)base.CreateInstanceCore(context);
// assign whatever settings you need here
return series;
}
}