BCS impersonation with WCF

Hi All,

I am using Business Connectivity Services which connects to SOAP WCF, Below is the connection properties image of the external content type and the read list operation in WCF

        [OperationBehavior(Impersonation = ImpersonationOption.Required)]
        public Delegation Retrieve_Delegation(int DelegationID)
        {
            string CurrentuserName = OperationContext.Current.ServiceSecurityContext.WindowsIdentity.Name;
             string ImpersonationLevel = OperationContext.Current.ServiceSecurityContext.WindowsIdentity.ImpersonationLevel.ToString();

         
        }

I am receiving  "Identification" in the ImpersonationLevel string instead of "Impersonation". we have setup Keberos authentication for the web application and the app pool account is been set for the "Unconstrained delegation". I have set up the WCF for using windows authentication.

Please help!