I am currently using xmlHTTP component to generate Web Service requests which are document-centric rather than the RPC requests which fit within the standard .Net pattern in a c# windows app. The implementation is pushed further outside the standard approach by need to explicitly control the namespace both within the SOAP Header and Body. The solution works fine when posting over HTTP, however I have seen from a number of articles that it will problematic when I introduce a security model based on certificates. My question is what should I use in its place to deliver the capability?