Bug#526102:

[maximilian attems <max@stro.at>]

On Mon, 18 May 2009, Maximi89 wrote:

>  i have the same problem as you... some files are saved on:
> maximi89@Maximiliano:~$ sudo ls -l /var/lib/initramfs-tools/
> total 8
> -rw-r--r-- 1 root root 72 ago 21  2008 2.6.18-5-486
> -rw-r--r-- 1 root root 72 feb 19 01:58 2.6.18-6-486
> 
> so, when update-initramfs are upgrading create some files, but when delete
> the kernel why don't delete the old files?...
> 
> the same happen with /lib/modules
> the old kernels leave their modules there...
> 

this bugs are fixed are in no sense related to the bug you filed.
for old packages just clean them up by hand.