We finally manage to build a working 1on1 TS server. Below you can find all the server details:

• IP: 188.138.115.98:27990
• Slots: 8 (Max 2 players can enter the game)
• Gametype: Team Survivor
• Mapcycle: ut4_turnpike, ut4_dressingroom (other maps can be voted as NextMap)

Server rules:

As explained above only 2 players can actually join the game, other will be auto-forced to spectators. The entire game is regulated by a Waiting List. All the connected people have to join this Waiting List in order to take part to the game.
When a map is over, the player who win the match will stay in-game, the other one will be auto-forced to spectators and added at the Bottom of the Waiting List, so another player can take his place (picked up from the Top of the Waiting List).
If happens that someone Disconnect he will be auto-removed from the Waiting List and if he was actually playing the game, another players will be picked up from the Waiting List and the map get restarted.
If someone join spectators while playing the game, he get removed from the Waiting List and added again at the bottom. The map get restarted and the 1st players with WAITING status in the Waiting List get picked up and pulled into the game to start a new match.

B3 commands:

• !join - Join the Waiting List. It's necessary that all the people that wants to join the game type !join in chat.
• !quit - Remove yourself from the Waiting List (You will be also forced to spectators). Just in case u want to only spec the game without taking part to it.
• !last - Move youself at the bottom of the Waiting List (This command can be used only by spectators)
• !wlist - Displays the Waiting List status
• !fix - Fix players teams. On a new map, can happen that a player takes a lot of time in loading the map, and another one can do AutoJoin and enter the game. That's the only case of 2vs1. When this happen, the guys who SHOULD stay in-game can use this command to Fix players teams (so the intruder will be forced again to spectators). All the other players cannot access this command