SOAP error. Need urgent help.

[Indrasish N Basuroychowdhury <in...@fanniemae.com>]

I am getting a SOAP error after sending the following SOAP envelope. Need help
desparately. Any help will be appreciated.

<SOAP-ENV:Body>
<ReturnService xmlns="http://localhost/FirstTry/WebServices/">
<ah><Username>User</Username><Password>Pass</Password></ah>
</ReturnService>
</SOAP-ENV:Body>

SOAP error is following:
Env:[Attributes={ xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"
xmlns:xsi="http://www.w3.org/1999/XMLSchema-instance"
xmlns:xsd="http://www.w3.org/1999/XMLSchema"}] [Header=null]
[Body=[Attributes={}] [BodyEntries=]] [EnvelopeEntries=]
SOAP Message:<?xml version="1.0" encoding="utf-8"?>
<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
  <soap:Body>
    <soap:Fault>
      <faultcode>soap:Server</faultcode>
      <faultstring>System.Web.Services.Protocols.SoapException: Server was
unable to process request. ---&gt; System.Exception: There was an error
generating the XML document. ---&gt; System.Exception: The type
fanniemae.TestArray.ReturnObj was not expected. Use the XmlInclude or
SoapInclude attribute to specify types that are not known statically.
   at System.Xml.Serialization.XmlSerializationWriter.WriteTypedPrimitive(String
name, String ns, Object o, Boolean xsiType)
   at
n2499d7d93ffa468fbd8861780677ee41.XmlSerializationWriter1.Write2_Object(String
n, String ns, Object o, Boolean isNullable, Boolean needType)
   at
n2499d7d93ffa468fbd8861780677ee41.XmlSerializationWriter1.Write4_ReturnServiceResponse(Object[]
p)
   at System.Xml.Serialization.XmlSerializer.Serialize(XmlWriter xmlWriter,
Object o, XmlSerializerNamespaces namespaces)
   at System.Xml.Serialization.XmlSerializer.Serialize(XmlWriter xmlWriter,
Object o)
   at System.Web.Services.Protocols.SoapServerProtocol.WriteReturns(Object[]
returnValues, Stream outputStream)
   at System.Web.Services.Protocols.WebServiceHandler.WriteReturns(Object[]
returnValues)
   at System.Web.Services.Protocols.WebServiceHandler.Invoke()
   at
System.Web.Services.Protocols.WebServiceHandler.CoreProcessRequest()</faultstring>

      <detail />
    </soap:Fault>
  </soap:Body>
</soap:Envelope>

The http requst and response is following:
The following is a sample SOAP request and response. The placeholders shown need
to be replaced with actual values.

POST /FirstTry/WebServices/Array/TestArray.asmx HTTP/1.1
Host: localhost
Content-Type: text/xml; charset=utf-8
Content-Length: length
SOAPAction: "http://localhost/FirstTry/WebServices/ReturnService"

<?xml version="1.0" encoding="utf-8"?>
<soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:xsd="http://www.w3.org/2001/XMLSchema"
xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
  <soap:Body>
    <ReturnService xmlns="http://localhost/FirstTry/WebServices/">
      <ao>
        <ArrayObj>
          <Username>string</Username>
          <Password>string</Password>
        </ArrayObj>
        <ArrayObj>
          <Username>string</Username>
          <Password>string</Password>
        </ArrayObj>
      </ao>
    </ReturnService>
  </soap:Body>
</soap:Envelope>
HTTP/1.1 200 OK
Content-Type: text/xml; charset=utf-8
Content-Length: length

<?xml version="1.0" encoding="utf-8"?>
<soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:xsd="http://www.w3.org/2001/XMLSchema"
xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
  <soap:Body>
    <ReturnServiceResponse xmlns="http://localhost/FirstTry/WebServices/">
      <ReturnServiceResult>
        <Object />
        <Object />
      </ReturnServiceResult>
    </ReturnServiceResponse>
  </soap:Body>
</soap:Envelope>


Thanks,

Indrasish.