Modified conffile not detected on package upgrade

[Malte Forkel <malte.forkel@berlin.de>]

Hello,

I have a question regarding the handling of locally modified conffiles
on package upgrades.

When I installed a new version of a self-written native package, I
noticed that I was not asked whether I wanted to keep or replace a
configuration file that I had modified locally. After the upgrade, my
modified version was still in place and there was no *.dpkg-dist.

The file resides in a subdirectory of /etc, and seems to be recognized
as a conffile: It gets removed by apt-get purge but not by apt-get
remove. Using dpkg-deb -c, I verified that the file is part of the new
package.

I'm running a fairly generic installation of Debian wheezy.

What might I be missing?

Thanks
Malte