I'm developing silverlight app with WCF Ria service. I'm using MS SQL database and Entity Framework as ORM framework (Database first method). Model with domain service are in separate project - App1.Data. Silverlight and generated model proxy classes are in App1 project. I want to add property to model entity class EntityClass to get this property on client side. So I did it that way - added this class to project App1.Data: public partial class EntityClass { [DataMember] public List<EntityClass2> PropertyName {get; set;} } After rebuilding EntityClass proxy on client side doesn't have this new property. Where is my mistake?