OK. After research I found that in Silverlight you need to use Enitity Model only without that not possible.
If you need to use ADO.Net, create a WCF service with a method to call Stored Procedure.
Then you can call that WCF service with ADO.Net
http://www.codeproject.com/Articles/37393/4-Simple-Steps-to-Consume-WCF-Service-using-Silver
http://www.codeproject.com/Articles/262164/Using-WCF-Service-with-Silverlight