inteligently downgrade packages?

[Jason Pepas <j.pepas@mail.utexas.edu>]

I recently wanted to install perlmagick, which depends on an older version of 
perl-api than the one currently on my system.

This can be remedied by specifying which branch of perl I want (ie, 
perl/testing), however, this causes all the packages which depend on my 
current version of perl-spi to be removed.

My question is, does there exist a way to tell apt to downgrade a package, and 
attempt to downgrade dependant packages instead of removing them?

here are the specifics of my situation:

(pts/12)root@marsala:~$ apt-get install perlmagick
Sorry, but the following packages have unmet dependencies:
  perlmagick: Depends: perlapi-5.6.1

(pts/12)root@marsala:~$ apt-get -f install perlmagick
(same thing...)

(pts/12)root@marsala:~$ apt-get install perl/testing 
Selected version 5.6.1-7 (Debian:testing, Debian:3.0r1a/stable) for perl
Sorry, but the following packages have unmet dependencies:
  perl: Depends: perl-base (= 5.6.1-7) but 5.8.0-15 is to be installed

(pts/12)root@marsala:~$ apt-get install -t testing perl        
Sorry, perl is already the newest version.

This is what finally worked:

(pts/12)root@marsala:~$ apt-get install perl/testing perl-base/testing 
perl-modu
les/testing perl-doc/testing docbook-utils/testing jadetex/testing 
tetex-extra/t
esting fttools/testing libft-perl/testing libjcode-pm-perl/testing 
perl-tk/testi
ng
Reading Package Lists... Done
Building Dependency Tree... Done
Selected version 5.6.1-7 (Debian:testing, Debian:3.0r1a/stable) for perl
Selected version 5.6.1-7 (Debian:testing, Debian:3.0r1a/stable) for perl-base
Selected version 5.6.1-7 (Debian:testing, Debian:3.0r1a/stable) for 
perl-modules
Selected version 5.6.1-7 (Debian:testing, Debian:3.0r1a/stable) for perl-doc
Selected version 0.6.12-3 (Debian:unstable) for docbook-utils
Selected version 3.12-2 (Debian:unstable, Debian:3.0r1a/stable) for jadetex
Sorry, jadetex is already the newest version.
Selected version 1.0.2+20011202-3 (Debian:testing) for tetex-extra
Selected version 1.2-13 (Debian:testing, Debian:3.0r1a/stable) for fttools
Selected version 1.2-13 (Debian:testing, Debian:3.0r1a/stable) for libft-perl
Selected version 0.73-1 (Debian:testing, Debian:3.0r1a/stable) for 
libjcode-pm-p
erl
Selected version 1:800.024-1 (Debian:testing, Debian:3.0r1a/stable) for 
perl-tk
The following packages will be DOWNGRADED
  fttools libft-perl libjcode-pm-perl perl perl-base perl-doc perl-modules
  perl-tk tetex-extra 
1 packages upgraded, 0 newly installed, 9 downgraded, 0 to remove and 300  not 
u
pgraded.
Need to get 15.4MB/19.3MB of archives. After unpacking 15.2MB will be freed.
Do you want to continue? [Y/n] 

-jason pepas