Today on Silverlight TV, Deepesh Mohnani answers four of the questions most frequently asked in the popular WCF RIA Services forums. This is a great episode to watch and the first in a periodic series from the RIA Services team in which we will address the top questions from developers.   In this episode, Deepesh addresses the following questions: POCO model How do I pull data from a non-ef data source? How do I do CUD on that? Client Side Computed Properties How do I create a client side computed property like total amount? How do I update a computed property when one of the dependency property changes? Protect my service How do I control access to methods? How do I control access by Roles? Windows Authentication How do I enable Windows Authentication? How do I integrate with Active Directory properties? Relevant links: John’s blog and on Twitter (@john_papa) Deepesh's Blog and on Twitter (@deepeshm) More about RIA Services  RIA Services Forums Follow us on Twitter @SilverlightTV or on the web at     Are you developing with Windows Phone 7? You can pre-order Learning Windows Phone Programming by Jaime Rodriguez, Yochay Kiriaty, and John Papa! Or check out the book's website.