[Freeswitch-users] debian repositories and gpg key no longer valid.

Hello. I want to install freeswitch on my debian squeeze. I've put deb http://files.freeswitch.org/repo/deb/debian/ squeeze main in my soiurces.list, like said in http://wiki.freeswitch.org/wiki/Installation_Guide. Then I did update apt-get. curl http://files.freeswitch.org/repo/deb/debian/freeswitch_archive_g0.pub | apt-key add - apt-get update. I've a gpg error it said that the key is not valid. Where can I put a valid key? Thank you.