The IRequest::get_ClientCertificate method retrieves the ClientCertificate collection of the Request object.
HRESULT get_ClientCertificate( IRequestDictionary ** ppDictReturn //pointer to an // IRequestDictionary interface // pointer that receives the // ClientCertificate collection );
You can iterate through the ClientCertificate collection with the get__NewEnum method exposed by the IRequestDictionary interface. You can also retrieve a specific ClientCertificate value with the get_Item method.