My mistake. Now I know what you meant - you want detect what channel is
used in your web service method.
I don't think you can do this. Web service is at a higher layer over
the transport layer such as HTTP. It can be over other tranport layer
(https for example). Maybe other, if any. It defeat it's purpose if you
have to care what mechnism is used to tranfer the data.
If your data is of critical information - such as credit card, etc. you
make it available only through SSL. You can set it up through IIS. I
just don't understand why want do this.