Install dependencies automatically from backports.

["dE ." <de.techno@gmail.com>]

I was wondering if apt can be configured to install the required 
dependencies from backports automatically, if the dependencies can't be 
fulfilled from the stable repository.

This's pretty common with Debian multimedia packages which require 
packages from backports.

Notice, by default apt should not prefer installing from backports if 
the required dependency can be fulfilled without using it.

This's my current /etc/apt/preferences -

Package: *
Pin: release a=stable
Pin-Priority: 989

Package: *
Pin: release a=squeeze-backports
Pin-Priority: 499

Package: *
Pin: release a=testing
Pin-Priority: 99

# not working
Package: *
Pin: release o=Unofficial Multimedia Packages
Pin-Priority: -100

Also another question which someone may like to answer is -- why am I 
not able to disable the Debian multimedia repository with the above 
preferences?