"downgrade" to stable

[nuxer@free.fr]

Before the woody release, I was using testing and unstable.
I did a few apt-get upgrade even once woody was released as stable.
Now, I'd like to remove the testing+unstable packages I got.

So, as stated in apt howto, I created /etc/apt/apt.conf :
---
APT::Default-Release "stable";
---

And /etc/apt/preferences :
---
Package: *
Pin: release a=stable
Pin-Priority: 1001
---

But when I issue an "apt-get dist-upgrade", it still fetch packages from testing
and unstable.
( I leave testing+unstable in my sources.list as I may want to "apt-get -t
testing package". Btw, is "apt-get package/testing" the same ?)

Did I miss something ?