Even though I'd like to see such a feature, the according package didn't 
receive any updates since 2 years and no one stepped up in testing it for our 
needs. So closing this issue with "dead".

http://darcs.nomeata.de/cgi-bin/darcsweb.cgi?r=customdeb
http://www.joachim-breitner.de/blog/archives/279-guid.html

We should take a closer look at that, if that fits our need to adjust 
configuration files of different Debian packages, so we can ship conffiles 
without having to deal with dpkg-divert (which is very hackisch to handle for 
conffiles of course due to its nature).