WCF - Fake service interface

        public void CreateDebtor(AxdEntity_CustTable debtor)
        {
            HndDebtorsService service;
            string username = Thread.CurrentPrincipal.Identity.Name;

            WcfService custService = new WcfService("WSHttpBinding_HndDebtorsService", typeof (HndDebtorsServiceChannel), null);
            OperationContextScope oScope = new OperationContextScope((IClientChannel) custService.Channel);
            using (oScope)
            {
                AuthenticationHelper.SetHeader(username);

                service = factory.CreateInstance<HndDebtorsService>(custService);

                debtor.@class = "entity";

                HndDebtorsServiceCreateRequest customerServiceCreateRequest = new HndDebtorsServiceCreateRequest();

                AxdHndDebtors debtors = new AxdHndDebtors {CustTable = new AxdEntity_CustTable[1]};
                debtors.CustTable[0] = debtor;
                customerServiceCreateRequest.HndDebtors = debtors;

                Logger.Instance.Log("About to save customer", LoggerEnums.Severity.DEBUG, debtor);

                // I want to verify that service.create is called!
                HndDebtorsServiceCreateResponse response = service.create(customerServiceCreateRequest);

                Logger.Instance.Log("Customer saved, response:", LoggerEnums.Severity.DEBUG, response.EntityKeyList);
            }
        }

        [Test, Isolated]
        public void CreateDebtor_CreatingDebtor_CreateIsCalled()
        {
            // ARRANGE
            RS_DebtorService service = new RS_DebtorService();
            HndDebtorsService fakeService = Isolate.Fake.Instance<HndDebtorsService>();
            Isolate.Swap.NextInstance<HndDebtorsService>().With(fakeService);

            Isolate.WhenCalled(() => fakeService.create(null)).WillReturn(null);

            // ACT
            service.CreateDebtor(null);

            // ASSERT
            Isolate.Verify.WasCalledWithAnyArguments(() => fakeService.create(null));
        }