AFAIK, when connecting, before sending or receiving anything, you must put the TCP stream in SslStream, and then do the certificate checks with it, before moving on with normal operations. Said “normal” operations must be done on that same SslStream, so after the certificate checks, you’ll want to assign the SslStream to the “tcpStream” variable.
If you make something that works, please do post it somewhere and/or modify the wiki page.