I am afraid that RadHtmlChart does not support this functionality yet. Nevertheless it has already been logged as a feature request in our feedback portal here
, so that you can monitor, comment or vote on it. If the idea gets enough votes and approval from our management we will consider its implementation for our future releases.
the Telerik team
If you want to get updates on new releases, tips and tricks and sneak peeks at our product labs directly from the developers working on the RadControls for ASP.NET AJAX, subscribe to their blog feed