Jonathan, Dicebot,thank you very much for your response. So you are confirming my conclusion, that finalizers/destructors in D work pretty much like in C++ and there is no way to do Java/C#/Managed C++-like finalization.
For the records, since Dicebot asked: I am using DMD32 v2.063.2 on Debian 7.2
All the best, Florian.