[MessageContract]
 public class HelloResponseMessage
 {
   private string localResponse = String.Empty;
   private string extra = String.Empty;

   [MessageBodyMember(
     Name = "ResponseToGreeting",
     Namespace = "http://www.examples.com")]
   public string Response
   {
     get { return localResponse; }
     set { localResponse = value; }
   }

   [MessageHeader(
     Name = "OutOfBandData",
     Namespace = "http://www.examples.com",
     MustUnderstand=true
   )]
   public string ExtraValues
   {
     get { return extra; }
     set { this.extra = value; }
  }

  /*
   The following is the response message, edited for clarity.
   
   <s:Envelope>
     <s:Header>
       <a:Action s:mustUnderstand="1">http://HelloResponseMessage/Action</a:Action>
       <h:OutOfBandData s:mustUnderstand="1" xmlns:h="http://www.examples.com">Served by object 13804354.</h:OutOfBandData>
     </s:Header>
     <s:Body>
       <HelloResponseMessage xmlns="Microsoft.WCF.Documentation">
         <ResponseToGreeting xmlns="http://www.examples.com">Service received: Hello.</ResponseToGreeting>
       </HelloResponseMessage>
     </s:Body>    
   </s:Envelope>
   */
}