[syslog-ng]Filter postfix log messages

[Florian Lindner]

Hello,
I want to filter out all log messages from postfix. They look like these:

Nov  9 14:16:28 s_sys@bastet postfix/pickup[24484]: 4D92C4580B7: uid=30 
from=<wwwrun>
Nov  9 14:16:28 s_sys@bastet postfix/cleanup[24510]: 4D92C4580B7: 
message-id=<20031109131628.4D92C4580B7@bastet.centershock.net>

How can I do that?
I tried:

filter f_postfix { match(".{16,16}s_sys@bastet postfix"); };

But it doesn't work...
Thanks,
Florian