This is how you can get this achievement and all the other achievements. You want to open mods and look for Sepp and Sepp2. Then start a new game and you should get all the achievements including this one. *Warning* if you do not have the DLC for the 500 extra gamerscore you will not get this achievement. Tell me if Sepp and Sepp2 no longer pop-up in the mod menu by commenting, so I can edit this solution