public static void AddDataDisk(this IServiceManagement proxy,
                                string subscriptionId,
                                string serviceName,
                                string deploymentName,
                                string roleName,
                                DataVirtualHardDisk dataDisk)
 {
     proxy.EndAddDataDisk(proxy.BeginAddDataDisk(
                              subscriptionId,
                              serviceName,
                              deploymentName,
                              roleName,
                              dataDisk,
                              null,
                              null));
 }