apt/dpkg always upgrade still upgraded packages

[Peter Stoehr <lists@peter.st>]

Hi everyone,

I have a strange problem with apt. I backported Postfix and vnstat,
builded the Debian packages, installed them and put them into my
repository. Everythings works fine.

But, whenever I make "apt-get update && apt-get upgrade", apt want to
upgrade Postfix and Vnstat again and again. Did I something wrong when
building the packages?

<snip>

# apt-get upgrade
Reading Package Lists... Done
Building Dependency Tree... Done
The following packages will be upgraded:
  postfix postfix-mysql vnstat
3 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
Need to get 0B/1066kB of archives.
After unpacking 0B of additional disk space will be used.
Do you want to continue? [Y/n]
Preconfiguring packages ...
(Reading database ... 46905 files and directories currently installed.)
Preparing to replace vnstat 1.4-2.1 (using .../vnstat_1.4-2.1_amd64.deb) ...
Unpacking replacement vnstat ...
Preparing to replace postfix 2.2.10-2 (using
.../postfix_2.2.10-2_amd64.deb) ...
Stopping Postfix Mail Transport Agent: postfix.
Unpacking replacement postfix ...
Preparing to replace postfix-mysql 2.2.10-2 (using
.../postfix-mysql_2.2.10-2_amd64.deb) ...
Unpacking replacement postfix-mysql ...
Setting up vnstat (1.4-2.1) ...
Setting up postfix (2.2.10-2) ...

Postfix configuration was not changed.  If you need to make changes, edit
/etc/postfix/main.cf (and others) as needed.  To view Postfix configuration
values, see postconf(1).

After modifying main.cf, be sure to run '/etc/init.d/postfix reload'.

Running newaliases
Stopping Postfix Mail Transport Agent: postfix.
Starting Postfix Mail Transport Agent: postfix.

Setting up postfix-mysql (2.2.10-2) ...

# apt-get upgrade
Reading Package Lists... Done
Building Dependency Tree... Done
The following packages will be upgraded:
  postfix postfix-mysql vnstat
3 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
Need to get 0B/1066kB of archives.
After unpacking 0B of additional disk space will be used.
Do you want to continue? [Y/n] n
Abort.

<snap>

Rgds, Peter
-- 
Unofficial repository for AMD64:
PHP 5.1 - Postfix 2.2 - VNSTAT 1.4
deb http://peter.st/debian-amd64/ sarge main