The remote server returned an error: (500) Internal Server Error. web service error soap request - asp.net

Question

I want to create a web service that responds to soap requests. and returns a soap response.now i want to send 2 parameters to the service namely invoiceno and orderno do something with it at the webservice and return the result. currently im just trying to retuen the values recieved as it is back to the client, but i keep getting this error "The remote server returned an error: (500) Internal Server Error." I am a total novice with soap web services. please tell me what i am doing wrong. or is this completely wrong.
namespace WebApplication7
{
/// <summary>
/// Summary description for WebService1
/// </summary>
[WebService(Namespace = "http://tempuri.org/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
[System.ComponentModel.ToolboxItem(false)]
// To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line.
// [System.Web.Script.Services.ScriptService]
public class WebService1 : System.Web.Services.WebService
{
[WebMethod]
public XmlDocument savedata()
{
XmlDocument xmlSoapRequest = new XmlDocument();
Stream receiveStream = HttpContext.Current.Request.InputStream;
receiveStream.Position = 0;
string invoiceno2 = xmlSoapRequest.GetElementById("invoiceno").Value;
string orderno2 = xmlSoapRequest.GetElementById("orderno").Value;
string gg = #" <soap:Envelopexmlns:soap=""http://www.w3.org/2001/12/soap-envelope""soap:encodingStyle=""http://www.w3.org/2001/12/soap-encoding"">
<soap:Body xmlns:m=""http://www.example.org/stock"">
<m:savedata>
<m:invoiceno>" + invoiceno2 + #"</m:invoiceno>
<m:orderno>" + orderno2 + #"</m:orderno>
<m:haha>hahahahahahahha</m:haha>
</m:savedata>
</soap:Body>
</soap:Envelope>";
XmlDocument cv = new XmlDocument();
cv.LoadXml(gg);
using (StreamReader readStream = new StreamReader(receiveStream, Encoding.UTF8))
{
// Load into XML document
xmlSoapRequest.Load(readStream);
}
// string gg = invoiceno + " hahahahaha " + orderno;
return cv;
}
}
}
and this is the client i created to consume it
namespace unicommerce_testing
{
public partial class _Default : Page
{
protected void Page_Load(object sender, EventArgs e)
{
Response.Write(Execute());
}
public static string Execute()
{
HttpWebRequest request = CreateWebRequest();
XmlDocument soapEnvelopeXml = new XmlDocument();
soapEnvelopeXml.LoadXml(CreateOrEditItemTypeRequestCreator("44", "2500313-125","Watch",20,20,20,56,"This is a test product","Red","Brillier","NA",45000));
using (Stream stream = request.GetRequestStream())
{
soapEnvelopeXml.Save(stream);
}
using (WebResponse response = request.GetResponse())
{
using (StreamReader rd = new StreamReader(response.GetResponseStream()))
{
string soapResult = rd.ReadToEnd();
return soapResult;
}
}
}
/// <summary>
/// Create a soap webrequest to [Url]
/// </summary>
/// <returns></returns>
public static HttpWebRequest CreateWebRequest()
{
HttpWebRequest webRequest = (HttpWebRequest)WebRequest.Create(#"http://localhost:1234/test/WebService1.asmx/savedata");
webRequest.Headers.Add(#"SOAP:Action");
webRequest.ContentType = "text/xml;charset=\"utf-8\"";
webRequest.Accept = "text/xml";
webRequest.Method = "POST";
return webRequest;
}
public static string CreateOrEditItemTypeRequestCreator()
{
string request= #"<soap:Envelopexmlns:soap=""http://www.w3.org/2001/12/soap-envelope""soap:encodingStyle=""http://www.w3.org/2001/12/soap-encoding"">
<soap:Body xmlns:m=""http://www.example.org/stock"">
<m:savedata>
<m:invoiceno>inv1</m:invoiceno>
<m:orderno>od1</m:orderno>
</m:savedata>
</soap:Body>
</soap:Envelope>";
return request;
}
}
}