Pierreandre, that is a tutorial for people that made their sims to share with bodyshop and the requester specifically said that they are in-game sims created in CAS so that tutorial is not what the person needs.
You will need to use Sim-Pe in order to extract sims from your game, here is a tutorial on how to do that, just follow the Step 1 part only:
http://www.insimenator.org/showthread.php?t=18184Before you do all this, make sure you already have a subfolder call "SavedSims" in your sims2 folder since if the folder does not exist SimPe won't create it and it won't be able to save the sim you will extract.
Once that is done, you'll just need to .zip or .rar the package file created by the game and post them.