title: Add Custom SOAP Header
body: <p>I have a WSDL that does not expose the SOAP headers, but I need to add the following in to the header:</p>
  
  <pre><code>   &lt;soapenv:Header&gt;
      &lt;UsernameToken xmlns="http://siebel.com/webservices"&gt;ANONYMOUS&lt;/UsernameToken&gt;
      &lt;PasswordText xmlns="http://siebel.com/webservices"&gt;ANONYMOUS&lt;/PasswordText&gt;
      &lt;SessionType xmlns="http://siebel.com/webservices"&gt;None&lt;/SessionType&gt;
     &lt;/soapenv:Header&gt;
  </code></pre>
  
  <p>Is there anyway to do this in C# if these header values are not exposed?</p>