Cannot install linux-headers-2.6.32-bpo.3-686 - dependency problem with linux-kbuild-2.6.32

[Giovanni Toraldo <scurippio@gmail.com>]

Hi,

linux-headers-2.6.32-bpo.3-686 is broken without manually installing
linux-kbuild-2.6.32 from squeeze/sid.

# aptitude install linux-headers-2.6.32-bpo.3-686
Reading package lists... Done
Building dependency tree
Reading state information... Done
Reading extended state information
Initializing package states... Done
Reading task descriptions... Done
The following packages are BROKEN:
  linux-headers-2.6.32-bpo.3-686
The following NEW packages will be installed:
  linux-headers-2.6.32-bpo.3-common{a}
0 packages upgraded, 2 newly installed, 0 to remove and 2 not upgraded.
Need to get 4302kB of archives. After unpacking 27.4MB will be used.
The following packages have unmet dependencies:
  linux-headers-2.6.32-bpo.3-686: Depends: linux-kbuild-2.6.32 which
is a virtual package.
The following actions will resolve these dependencies:

Keep the following packages at their current version:
linux-headers-2.6.32-bpo.3-686 [Not Installed]

Score is -9881

cat /etc/apt/sources.list
deb http://ftp.it.debian.org/debian/ lenny main contrib non-free
#deb-src http://ftp.it.debian.org/debian/ lenny main contrib non-free

deb http://security.debian.org/ lenny/updates main contrib non-free
#deb-src http://security.debian.org/ lenny/updates main contrib non-free

deb http://volatile.debian.org/debian-volatile lenny/volatile main
#deb-src http://volatile.debian.org/debian-volatile lenny/volatile main

#deb http://ftp.it.debian.org/debian/ sid main contrib non-free
#deb-src http://ftp.it.debian.org/debian/ sid main contrib non-free

deb http://www.backports.org/debian/ lenny-backports main contrib non-free

-- 
Giovanni "scorp" Toraldo