How to write quarters on X-Axis labels in Telerik's RadChart?

Question

I am using the Telerik's RadChart control that displays some time-based data on a chart. Timestamp is the X-axis dimension.

The control lets me set the label format for that axis, and that's the same format used by DateTime.ToString() method. For example:

"yyyy-mm-dd" would produce dates like 2011-11-18.

However, I'd like to categorize the data by the Quarters (I,II,III,IV). There is no such format specifier nor does the DateTime deals with Quarters.

Is there any way to define the quarter (via format specifiers), or delegate the process of writing the label to a custom function (via some Telerik RadChart's settings)?

Answer 1

I have made something like this:

http://www.telerik.com/community/forums/metro/chart-xaml/labeling-the-radcartesianchart-categorical-axis.aspx#2330414