>The sample client use soap toolkit COM for the client access.
>I have to build the equivalent of the 'ClientHeaderHandler' COM object to make this work...
>

You can create a Runtime callable wrapper. Right click on the project, go to Add reference..., click on the COM page and try to find your COM component.

You should be able to then create a reference to the COM component using the "new" keyword. Look for help on COM Interop services.

-Dave