Is the following correct? You are making a call to a WCF service that has DataContact(IsReference=true) set. You are calling the WCF service which returns the object in Silverlight but when you attempt to add the object to the Enterprise Library Isolated
Storage Cache you get an exception.
What exception are you receiving? What serialization are you using with the WCF service?
I suspect you have circular references which are causing the DataContractJsonSerializer to throw an exception.
Enterprise Library support engineer