private void sendInvoiceButton_Click(object sender, EventArgs e)
{
INVOICMessage invoice = new INVOICMessage();
invoice.Sender = invoiceSender.Text.ToUpper();
invoice.Recipient = invoiceRecipient.Text.ToUpper();
invoice.InvoiceNumber = invoiceNumber.Text.ToUpper();
invoice.ItemDescription = invoiceItemDescription.Text.ToUpper();
invoice.DueDate = invoiceDueDate.Value.ToString("yyMMdd");
invoice.Reference = invoiceReference.Text.ToUpper();
invoice.Amount = invoiceAmount.Text.ToUpper();
invoice.Currency = invoiceCurrency.Text.ToUpper();
INVOICMessageAdress adress = new INVOICMessageAdress();
adress.Street = invoiceStreet.Text.ToUpper();
adress.City = invoiceCity.Text.ToUpper();
adress.Zipcode = invoiceZipcode.Text.ToUpper();
adress.Country = invoiceCountry.Text.ToUpper();
invoice.Adress = adress;
DefaultClient proxy = new DefaultClient();
proxy.ClientCredentials.UserName.UserName = "******";
proxy.ClientCredentials.UserName.Password = "******";
InvoiceResult result = proxy.Operation_1(invoice);
MessageBox.Show(result.Result);
}