Currently, we don't have an example with external window and recurrences, but we plan to implement the necessary features for RadScheduler which will allow easy implementation of this scenario. Also, we will extend the online example to include recurrences.
Here are the online resources related to recurrence:
The recurrence engine
How to display all RadScheduler appointments in GridView
Should you have any other questions, please feel free to contact us.
the Telerik team