Debian wheezy: unattended upgrades

[Aaron Marks <aaronmarks90@yahoo.com>]

I am using Debian wheezy and unattended-upgrades. I would like to install all updates automatically.

That's my sources.list:
deb http://ftp.de.debian.org/debian/ wheezy main non-free contrib
deb-src http://ftp.de.debian.org/debian/ wheezy main non-free contrib

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


and that's my 50unattended-upgrades:
Unattended-Upgrade::Allowed-Origins {
"Debian wheezy";
"Debian wheezy/updates";
};


Unfortunately new packages are not installed. That's what my unattended-upgrades.log looks like:
2012-03-11 07:03:24,239 INFO Initial blacklisted packages: 
2012-03-11 07:04:15,883 INFO Starting unattended upgrades script
2012-03-11 07:04:21,575 INFO Allowed origins are: ['o=Debian,a=wheezy', 'o=Debian,a=wheezy/updates']
2012-03-11 07:05:39,411 INFO No packages found that can be upgraded unattended


What's wrong?

Thanks a lot

A.