No package signature check for specific repository

[Georgi Alexandrov <georgi.alexandrov@gmail.com>]

Hello list,

I'm using debian unstable and the main debian unstable repositories to 
update my system.
I have added the ftp://ftp.nerim.net/debian-marillat/ repository to my 
sources.list file.
Works great, but every time I deal with apt-get or aptitude I get notified:

"W: GPG error: ftp://ftp.nerim.net sid Release: The following signatures 
couldn't be verified because the public key is not available: NO_PUBKEY 
07DC563D1F41B907"

I want to turn off gpg check fot that particular respository, is that 
possible?


thanks in advance,
Georgi Alexandrov