There is a way to do this. You can check the following post which shows it: Draw a chart with a mouse click
In addition, there is a method that gives you the location of a specific value on the axis:
var axis = radChartView1.Axes
var loc = axis.GetLocationOfValue(10);
I want to say that the feature is already completed and it will be released with the new version later today.
Should you have any other questions do not hesitate to ask.