Hi Andrea Rapuzzi,
Firstly, please excuse me for the late replied.
The issue has already been resolved and the fix is available both in our Latest Internal Build and in our Q1 2011 Beta release. I am sending you a sample project using the binaries from our internal build so that you can immediately test it.
the Telerik team
Registration for Q1 2011 What’s New Webinar Week is now open. Mark your calendar for the week starting March 21st and book your seat
for a walk through all the exciting stuff we ship with the new release!