Not to sure about servers not showing up, but if you just have friends joining, you could give them the direct connect IP info.
My server doesn't show in the list either, fwiw. (didnt really look hard though)
In your server control panel, there should be a row of buttons: start | stop | restart | launch | share
Its above and to the right of the FTP info you are looking at. That port is for an ftp connection to the server, not playing the game.
Either use the launch button and allow your browser to launch Steam and connect.
Or below the Server Detail block with the little map, there should be and IP address with an "i" in a white circle.
For Direct Connect IP is the IP address listed and the Game Port is the port you use. If the IP and port need to be on the same line(I've never used Direct before) the format will be xxx.xxx.xxx.xxx:xxxxx IP Address colon Game Port.
Hopefully that helps.