Hello there,
please make sure yoou have installed the LobbyPlugin, you can find it in the Sync under "Lobby".
If you did so and you still are not listed take a look in your RF2 root folder wether there is a folder called "Plugins". If not, then create it in your root folder and copy the BockbierbudeLobbyPlugin.dll and the .lua from the "Bin32/Plugins" or "Bin64/Plugins" (depends on your OS) by hand in that folder.
Then everything should work fine.