Thanks for your fast reply.
The flaw I am talking about is the possibility for attackers to get access to the encrypted data as descripted here:
My goal is to have a full encrypted NAS-volume with the full responsibility on my side. Meaning: If I lose the password, there shall be no way by any means to access this data. Doesn´t matter how much knowledge is needed to carry out an successful attack. There shall be just no way with today technical methods to access the encrypted data if you don´t know the password.
Of course I am fully aware of the risks coming with a true full volume encryption without any rescue- or possible attacking-pathes. But that´s what I would like to have. Like a full encrypted TrueCrypt-Volume: No password, no access by any means.