Indeed.
To enter subgame2 with ss you need to make sure AllowVIEClients=1 in server.ini under the Misc section and also ContinuumOnly=0 in server.cfg also under Misc section.
Or you can add your name to a new line in vip.txt. That's a file that should be in the same folder as subgame2.exe, if it's not there just make a new file.