Ok so im finaly up for doing my last 4 achievements on l4d2. They aint hard but well... Im lazy ;]
So if someone wants to help im allmost everyday online.

Hi, I have a free guest passes for Counter Strike: Source and Day of Defeat: Source.
If interested, leave a comment here and I will give it ya :P

Here it is:
http://www.youtube.com/user/L4DAchievementSlaves?feature=mhum

Only 2 videos at the moment, but if anyone would like to make more videos with me, or would like to submit their own, let me know :D

We are looking for any videos that would be beneficial to those who seek achievements!

Since this is by far the most sought after achievement in Left 4 Dead 2, and because I have wasted so many hours of my life trying to help people get it, I have decided to compile this simple guide (with compliments to Rager's Replacement: The King of SiN)

GET 4 HELPERS - Yourself + 4 other players (thats 5 GUYS) who are willing to help. You can use this group to find people to help by posting comments/ announcments.

MAKE FRIENDS WITH YOUR CREW - Team versus only allows friends to join the game, so buddy up!

PICK 2 HOSTS - Choose 2 players to host who will connect easily, for example 2 German players. I tried to connect UK to Argentina and it WOULDNT ♥♥♥♥♥♥♥ WORK, so pick 2 hosts that don't live a million ♥♥♥♥♥♥♥ miles apart. :P

SET UP 2 GAMES - Decide a 'winning' host and a 'losing' host. Losing host creates a TEAM VERSUS match (best to set it to Official dedicated and chose the final chapter of a campaign cos it will be quicker)
The winning host can set up his/her game to search for ANY CAMPAIGN.

JOIN THE LOSING HOST FIRST- Start by having the remaining players (the non-hosts) join the losing host's lobby. Once he has a full lobby, losing host can then begin to search for a game. As soon as he initiates the search, the non host players leave and join the winning host, who then starts the search also.
(Don't worry about leaving the loser's lobby! Despite what it says in the achievement's description, you do not need 4 vs 4. you only need 4 players to SEARCH for an opponent team.

HOPEFULLY YOU CONNECTED TO EACH OTHER- (and didn't join a bunch of random ♥♥♥♥)

WIN THE GAME- Now all you have to do is beat the loser host. hopefully he will be cooperative and let you kill him, but if not remember that you outnumber him 4 TO ♥♥♥♥♥♥♥ 1! Win the game and get your achievement.
Oh and if the loser host also needs the achievement, be nice and vote rematch and let him win :D

1. Install L4D2 Dedicated server from Library->Tools.
2. Install Metamod:Source and SourceMod on it.
3. Make yourself root admin (obviously).
4. (Optional) Install AdminCheats plugin for more fun. (Look for it @ SM forum).
5. Create server.cfg in cfg folder with the following contents:
sv_allow_lobby_connect_only 0
sv_steamgroup_exclusive 1
6. Start server.
7. Go to console, type:
sm_cvar sb_all_bot_game 1
map c1m4_atrium teamscavenge
8. Start L4D2, there should be your server under "Steam group servers".
9. Select it, check that it says "Team Scavenge".
10. Connect to it.
11. You should be now playing with bots, you just need to win against them, they don't know how to get gas cans, so all you have to do is to get 1 can per round.
TIPS: When you start to play as survivor, type "sm_cvar god 1" in console. When you start to play as infected, revert this by typing "sm_cvar god 0". If you have installed AdminCheats, enjoy "z_spawn witch" or similar.