Today I have finished a working demonstration using AJAX as a TCP connection. With that demonstration you can use a HTTP connection as a real TCP/IP connection:
var r = new AjaxPro.Web.Connection("/ajaxpro/tcp.ashx");
r.ondata = OnReceive;
With that demonstration code I could use the HTTP connection i.e. as a connection to get my emails (using POP3 protocol, on the server I hold a TCP/IP connection to my mail server). I will do some more tests later and put the source code and a working web site online. Your comment...!