SOAP Client in C# without access to a WSDL-file

string EndPoints = "http://203.189.91.127:7777/services/spm/spm";

string New_Xml_Request_String = "<?xml version="1.0" encoding="UTF-8"?><soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"><soapenv:Body><OTA_AirLowFareSearchRQ EchoToken="0" SequenceNmbr="0" TransactionIdentifier="0" xmlns="http://www.opentravel.org/OTA/2003/05"><POS xmlns="http://www.opentravel.org/OTA/2003/05"><Source AgentSine="" PseudoCityCode="NPCK"  TerminalID="1"><RequestorID ID=""/></Source><YatraRequests><YatraRequest DoNotHitCache="true" DoNotCache="false" MidOfficeAgentID="" AffiliateID="" YatraRequestTypeCode="SMPA"/></YatraRequests></POS><TravelerInfoSummary><AirTravelerAvail><PassengerTypeQuantity Code="ADT" Quantity="1"/><PassengerTypeQuantity Code="CHD" Quantity="1"/><PassengerTypeQuantity Code="INF" Quantity="1"/></AirTravelerAvail></TravelerInfoSummary> <SpecificFlightInfo><Airline Code=""/></SpecificFlightInfo><OriginDestinationInformation><DepartureDateTime>" + DateTime.Now.ToString("o").Remove(19, 14) + "</DepartureDateTime><OriginLocation CodeContext="IATA" LocationCode="DEL">" + Source + "</OriginLocation><DestinationLocation CodeContext="IATA" LocationCode="BOM">" + Destincation + "</DestinationLocation></OriginDestinationInformation><TravelPreferences><CabinPref Cabin="Economy"/></TravelPreferences></OTA_AirLowFareSearchRQ></soapenv:Body></soapenv:Envelope>";


 protected string HttpSOAPRequest_Test(string xmlfile, string proxy)
    {
        try
        {
            System.Xml.XmlDocument doc = new System.Xml.XmlDocument();
            doc.InnerXml = xmlfile.ToString();
            HttpWebRequest req = (HttpWebRequest)WebRequest.Create(EndPoints);
            req.Timeout = 100000000;
            if (proxy != null)
                req.Proxy = new WebProxy(proxy, true);
            req.Headers.Add("SOAPAction", "");
            req.ContentType = "application/soap+xml;charset="utf-8"";
            req.Accept = "application/x-www-form-urlencoded"; //"application/soap+xml";
            req.Method = "POST";
            Stream stm = req.GetRequestStream();
            doc.Save(stm);
            stm.Close();
            WebResponse resp = req.GetResponse();
            stm = resp.GetResponseStream();
            StreamReader r = new StreamReader(stm);
            string myd = r.ReadToEnd();
            return myd;
        }

   catch (Exception se)
        {
            throw new Exception("Error Occurred in AuditAdapter.getXMLDocumentFromXMLTemplate()", se);
        }
    }

Imports Microsoft.Web.Services3
Imports Microsoft.Web.Services3.Addressing
Imports Microsoft.Web.Services3.Messaging

Namespace Logic
    Public Class HTTPClient
        Inherits Soapclient

        Sub New(ByVal destination As EndpointReference)
            MyBase.Destination = destination
        End Sub

        <SoapMethod("processConfirmation")> _
        Public Function processConfirmation(ByVal envelope As SoapEnvelope) As SoapEnvelope
            Return MyBase.SendRequestResponse("processConfirmation", envelope)
        End Function
    End Class
End Namespace

Dim hc As New HTTPClient(New Microsoft.Web.Services3.Addressing.EndpointReference(New System.Uri("http://whatever.srv")))

Dim envelope As New Microsoft.Web.Services3.SoapEnvelope
Dim doc As New Xml.XmlDocument
doc.LoadXml("<hey>there</hey>")
envelope.SetBodyObject(doc)

Dim return_envelope As Microsoft.Web.Services3.SoapEnvelope = hc.processConfirmation(envelope)