How to add extra soap header information

Hi

I have already tried to search on SCN, Google etc. so I hope that somebody here have the solution.

Problem:

Integration to ByDesign.

sending Purchase Order Acknowledgment to ByDesign

Ok... I have the WSDL from the configured web service

From the WSDL I have created C# proxy classes

When the request is send to ByDesign I get the following error:

<soap-env:Envelope xmlns:soap-env="http://schemas.xmlsoap.org/soap/envelope/">

   <soap-env:Header/>

   <soap-env:Body>

      <soap-env:Fault>

         <faultcode>soap-env:Server</faultcode>

         <faultstring xml:lang="en">Web service processing error; more details in the web service error log on provider side (UTC timestamp 20131108153925; Transaction ID 00163E05F68F1EE392917E3F92DC3D65)</faultstring>

         <detail/>

      </soap-env:Fault>

   </soap-env:Body>

</soap-env:Envelope>

this is due to the fact that my request is missing the following:

   <soapenv:Header>

      <msgID:messageId xmlns:msgID="http://www.sap.com/webas/640/soap/features/messageId/">uuid:00163e02-a5da-1ee1-a7d5-e24f8067c508</msgID:messageId>     

   </soapenv:Header>

Note: uuid:xxxx should change on each request

How can I create the needed extra header information (It's not defined in the WSDL!)  in C# ?

Thanks in advance.

Kind regards