Onto your questions:
1.The series cannot be overlapped in such a manner. You can use a different chart type, if this setup does not meet your requirements well.
2. You can directly set the label for a datapoint, as shown below:
<telerikCharting:DataPoint YValue="154" XCategory="Jan" Label="custom text"/>
<telerikCharting:DataPoint YValue="138" XCategory="Feb"/>
<telerikCharting:DataPoint YValue="143" XCategory="Mar"/>
I hope this information helps.
the Telerik team
Do you want to have your say when we set our development plans? Do you want to know when a feature you care about is added or when a bug fixed? Explore the Telerik Public Issue Tracking
system and vote to affect the priority of the items