Currently this is not possible and the feature is still not on our immediate roadmap. However we find your request very reasonable, its priority compared to the upcoming tasks on the Report Server is lower now.
I would like to ask you to submit it on our feedback portal
so others can vote for it and increase its priority. How does it sound?
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?
Telerik Feedback Portal
and vote to affect the priority of the items