can't get the OTA_HotelResNotifRQ xml value in asp.net web service C#

I have trying to get the OTA_HotelResNotifRQ xml in asp.net web service. I have created the below xml as class in vs 2012 paste as xml to classes, and include one web service.

XML For Request -

 <?xml version="1.0" encoding="UTF-8"?>
    <SOAP-ENV:Envelope xmlns:SOAP-ENV="http://ift.tt/sVJIaE">
     <SOAP-ENV:Header xmlns:SOAP-ENV="http://ift.tt/sVJIaE">
      <wsse:Security xmlns:wsse="http://ift.tt/LRW8Ij" soap:mustUnderstand="1" xmlns:soap="http://ift.tt/sVJIaE">
       <wsse:UsernameToken>
        <wsse:Username>Mcubic</wsse:Username>
        <wsse:Password Type="http://ift.tt/1aTA7XU">KEwk0c96tAIYoHh</wsse:Password>
       </wsse:UsernameToken>
      </wsse:Security>
     </SOAP-ENV:Header>
     <SOAP-ENV:Body xmlns:SOAP-ENV="http://ift.tt/sVJIaE">
      <OTA_HotelResNotifRQ xmlns="http://ift.tt/NpIDks" Version="1.0" EchoToken="FCA9081A-ED61-2148-2D75-A13263D273D4" ResStatus="Commit" TimeStamp="2014-12-16T19:08:53+05:30">
       <POS>
        <Source>
        -------     <tags>---------
        </Source>
       </POS>
       <HotelReservations>
        <HotelReservation CreateDateTime="2014-12-16T18:45:15+05:30">
         <UniqueID Type="14" ID="14603"/>
         <RoomStays>
    -------     <tags>---------
          </RoomStay>
         </RoomStays>
         <ResGuests>
    -------     <tags>---------
         </ResGuests>
        </HotelReservation>
       </HotelReservations>
      </OTA_HotelResNotifRQ>
     </SOAP-ENV:Body>
    </SOAP-ENV:Envelope>

Soap Web service -

  [WebMethod]
        public XmlDocument Envelope(EnvelopeHeader EnvelopeHeader)
        {
            XmlDocument XmlDocumentObject = new XmlDocument();
            return XmlDocumentObject;
        }

While trying this web service i have got the below xml -

<?xml version="1.0" encoding="utf-8"?>
<soap:Envelope xmlns:xsi="http://ift.tt/ra1lAU" xmlns:xsd="http://ift.tt/tphNwY" xmlns:soap="http://ift.tt/sVJIaE">
  <soap:Body>
    <Envelope xmlns="http://tempuri.org/">
      <EnvelopeHeader>
        <Security ="" xmlns="http://ift.tt/LRW8Ij">
          <UsernameToken>
            <Username>string</Username>
            <Password xsi:nil="true" />
          </UsernameToken>
        </Security>
      </EnvelopeHeader>
    </Envelope>
  </soap:Body>
</soap:Envelope>

How can i write code for getting OTA_HotelResNotifRQ xml? Please help me.