VisionData.VisionData visionData = new VisionData.VisionData
            {
                Url = "http://w2sdata.way2send.pl/visiondata.asmx",
                Timeout = 60000,
                UserCredentialsValue = new UserCredentials()
                {
                    userName = username,
                    password = password
                }
            };
                DataSet dataSet = new DataSet();
                DataTable dataTable = new DataTable("VisionData");
                DataColumn dataColumn = new DataColumn("requestXML", typeof(String));
                dataTable.Columns.Add(dataColumn);
                dataSet.Tables.Add(dataTable);
                DataRow dataRow = dataTable.NewRow();
                dataRow["requestXML"] = "xml";
                dataSet.Tables["VisionData"].Rows.Add(dataRow);
                DataSet dataSetResult = visionData.exec("XML_OrdersSetReferenceNr", dataSet);
                return dataSetResult.Tables[0].Rows[0][0].ToString();