Hello Iurii,
You can use the attachment clipped to my colleague Konstantin's post or switch to the latest version 2010.3.1317 of RadControls for ASP.NET AJAX (should be available in your Telerik account's Product Files Download section).
Greetings,
Sebastian
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!