Once you have purchased the license, you should have the non-trial installation available for download in your Client.Net account. All you need to do is to replace the trial bits with the purchased ones.
In other words there are two different sets of dlls - trial with the trial messages included , and non-trial which you may reference in your production projects.
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!