After trying rjdimo and Solara's strategy in their "Complete Achievement Guide" like 10-15 times and failing each and every time, I started googling a solution. I quickly found a thread on TrueAchievements[www.trueachievements.com] in which a user named Tervaskanto[www.trueachievements.com] explained his method. This strat worked for me aswell as for other users of that forum on first try, so I wanted to share this information with you.

I'd like to add him as a contributor to this guide, but I couldn't find his Steam profile. I don't even know if he has one, since according to his profile on TrueAchievements he mainly plays on XBOX and there's no link to any Steam profile.