var store = new X509Store(StoreName.My, StoreLocation.CurrentUser);
            store.Open(OpenFlags.ReadOnly);
            var saCert = store.Certificates[0];


            // Create the binding.
            var myBinding = new BasicHttpBinding();
            myBinding.Security.Mode = BasicHttpSecurityMode.Transport;
            myBinding.Security.Transport.ClientCredentialType =
               HttpClientCredentialType.Certificate;


            // Create the endpoint address. Note that the machine name 
            // must match the subject or DNS field of the X.509 certificate
            // used to authenticate the service. 
            EndpointAddress ea = new
               EndpointAddress("https://RA-SA/RA/RA.asp");

           
           
           var cspInformations = new CCspInformations();

            cspInformations.AddAvailableCsps();

            var key = new CX509PrivateKey
            {
                ProviderType = (X509ProviderType)75,
                KeySpec = X509KeySpec.XCN_AT_SIGNATURE,
                KeyUsage = X509PrivateKeyUsageFlags.XCN_NCRYPT_ALLOW_ALL_USAGES,
                MachineContext = false,
                ExportPolicy = X509PrivateKeyExportFlags.XCN_NCRYPT_ALLOW_EXPORT_FLAG,
                CspInformations = cspInformations,
                ContainerName = Guid.NewGuid().ToString()
            };

            
            IX509CertificateRequestPkcs10 request = new CX509CertificateRequestPkcs10();
            request.InitializeFromPrivateKey(X509CertificateEnrollmentContext.ContextUser, key, null);

            // Задаем DN.
            request.Subject = new CX500DistinguishedNameClass();
            request.Subject.Encode(saCert.Subject);
            

            // Добавляем Extended Key Usage: Проверка подлинности клиента (1.3.6.1.5.5.7.3.2)
            var clientAuth = new CObjectId();
            clientAuth.InitializeFromName(CERTENROLL_OBJECTID.XCN_OID_PKIX_KP_CLIENT_AUTH);

            //  Пользователь Центра Регистрации, HTTP, TLS клиент (1.2.643.2.2.34.6)
            var tlsClient = new CObjectId();
            tlsClient.InitializeFromValue("1.2.643.2.2.34.6");

            var ekuIds = new CObjectIds { clientAuth, tlsClient };

            var ekuExtension = new CX509ExtensionEnhancedKeyUsage();
            ekuExtension.InitializeEncode(ekuIds);

            request.X509Extensions.Add((CX509Extension)ekuExtension);

            // Добавляем Key Usage: Digital Signature, Non-Repudiation, 
            // Key Encipherment, Data Encipherment (f0)
            var keyUsage = new CX509ExtensionKeyUsage();

            // ReSharper disable BitwiseOperatorOnEnumWithoutFlags
            keyUsage.InitializeEncode(
                CERTENROLLLib.X509KeyUsageFlags.XCN_CERT_DIGITAL_SIGNATURE_KEY_USAGE
                | CERTENROLLLib.X509KeyUsageFlags.XCN_CERT_NON_REPUDIATION_KEY_USAGE
                | CERTENROLLLib.X509KeyUsageFlags.XCN_CERT_KEY_ENCIPHERMENT_KEY_USAGE
                | CERTENROLLLib.X509KeyUsageFlags.XCN_CERT_DATA_ENCIPHERMENT_KEY_USAGE);
            request.X509Extensions.Add((CX509Extension)keyUsage);
            // ReSharper restore BitwiseOperatorOnEnumWithoutFlags

            // Кодируем запрос.
            request.Encode();

            // Объект, реализующий IX509Enrollment
            var enrollment = new CX509Enrollment();

            // Строка с запросом:
            enrollment.InitializeFromRequest(request);


            var contentInfo = new ContentInfo(Encoding.UTF8.GetBytes(enrollment.CreateRequest()));
            var signedCms = new SignedCms(contentInfo, false);

            
            var cmsSigner = new CmsSigner(saCert);
            signedCms.ComputeSignature(cmsSigner, true);
            var encode = signedCms.Encode();
            var requestStr = Convert.ToBase64String(encode);
            var client = new RaService.CertRequestSoapPortClient(myBinding, ea);
            client.ClientCredentials.ClientCertificate.Certificate = saCert;

           var requestId = client.SubmitRequest(requestStr, "1");
           Console.WriteLine(requestId);
            Console.ReadKey();