Consume AIF Inventory On Hand web service in AX PART 1 - SOAP request

Sample XML consumption in C# code to AIF Inventory On Hand. This is from AX 4.0 but I think it's the same in AX 2009.
try
{
     string strSoapEnvelope = "";
     string responseString = "";

     // Build SOAP envelope
     strSoapEnvelope = "<?xml version=\"1.0\" encoding=\"utf-8\"?>";
     strSoapEnvelope += "<soap12:Envelope xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" xmlns:xsd=\"http://www.w3.org/2001/XMLSchema\" xmlns:soap12=\"http://www.w3.org/2003/05/soap-envelope\">";
     strSoapEnvelope += "<soap12:Body>";
     strSoapEnvelope += "<findListInventoryOnhand xmlns=\"http://schemas.microsoft.com/dynamics/2006/02/documents/InventoryOnhand\">";
     strSoapEnvelope += "<DocumentContext>";
     strSoapEnvelope += "<MessageId>" + Guid.NewGuid().ToString() + "</MessageId>";
     strSoapEnvelope += "<SourceEndpointUser> DOMAIN \\WEBSERVICESUSER</SourceEndpointUser>";
     strSoapEnvelope += "<SourceEndpoint>XXXXXXXXXXXXXXXX</SourceEndpoint>";
     strSoapEnvelope += "<DestinationEndpoint>ENDPOINT NAME</DestinationEndpoint>";
     strSoapEnvelope += "</DocumentContext>";
     strSoapEnvelope += "<QueryCriteria xmlns=\"http://schemas.microsoft.com/dynamics/2006/02/documents/QueryCriteria\">";
     strSoapEnvelope += "<CriteriaElement>";
     strSoapEnvelope += "<DataSourceName>InventSum</DataSourceName>"; strSoapEnvelope += "<FieldName>ItemId</FieldName>";
     strSoapEnvelope += "<Operator>Equal</Operator>";
     strSoapEnvelope += "<Value1>YYYYYYYYYYYYYYYYYY</Value1>";
     strSoapEnvelope += "</CriteriaElement>";
     strSoapEnvelope += "</QueryCriteria>";
     strSoapEnvelope += "</findListInventoryOnhand>";
     strSoapEnvelope += "</soap12:Body>";
     strSoapEnvelope += "</soap12:Envelope>";
     MSXML2.XMLHTTP xmlHTTP = new XMLHTTP();
     xmlHTTP.open("Post", "http://ZZZ.ZZ.ZZ.ZZZ:ZZZZ/inventoryonhandservice.asmx", false, @"DOMAIN\WEBSERVICESUSER", " PASSWORD");
     xmlHTTP.setRequestHeader("Host", "99.999.99.99");
     xmlHTTP.setRequestHeader("Content-Length", strSoapEnvelope.Length.ToString());
     xmlHTTP.setRequestHeader("Content-Type", "application/soap+xml; charset=utf-8");
     xmlHTTP.send(strSoapEnvelope.ToString());

     responseString = xmlHTTP.responseText.ToString();
     MessageBox.Show(string.Format("XML: {0}", responseString.ToString()));

     WebClient webby = new WebClient();
     webby.Encoding = System.Text.Encoding.UTF8;
     webby.Credentials = new NetworkCredential("WEBSERVICESUSER ", "PASSWORD", " DOMAIN");
     webby.Headers.Add("Content-Type", "text/xml;");
     string stuff = webby.UploadString("http://99.999.99.999/inventoryonhandservice.asmx", "POST", strSoapEnvelope.ToString());

     MessageBox.Show(stuff);
}
catch (Exception ex)
{
     MessageBox.Show(ex.ToString());
}