public CustomerRegistrationResponse CustomerRegistration(CustomerRegistrationRequest request)
        {
            if (request == null)
                throw new ArgumentNullException("request");

            return SendGetRequest<CustomerRegistrationRequest, CustomerRegistrationResponse>(request, "CustomerRegistration");
        }
        public CustomerRegistrationResponse CustomerRegistration(string merchantCustomerID)
        {
            if (merchantCustomerID == null)
                throw new ArgumentNullException("merchantCustomerID");

            var request = new CustomerRegistrationRequest
            {
                MerchantCustomerID = merchantCustomerID
            };
            return CustomerRegistration(request);
        }