It's not documented here in the public forum, freddy asked me to patch the server executable, so that some commands, like game.killPlayer could be run.
You need to go to 0x00558268 address or 0x00158268 offset and change the byte value 75 to EB and save the file. After that, typing those commands from the server console won't prompt the "Unauthorized method" error message and they will be executed.