If you need to develop custom modules that rely on OpenAccess and RadControls, you have to download the latest version of our Sitefinity SDK 4.1 SP1
that includes the necessary tools for that. We will try to minimize the duration between the two releases to minimum, so that you don't experience such issues with enhancing your custom modules.
the Telerik team
Do you want to have your say in the Sitefinity development roadmap? Do you want to know when a feature you requested is added or when a bug fixed? Explore the Telerik Public Issue Tracking
system and vote to affect the priority of the items