[bitfolk] Debian postfix mail log rotation.

I never saw a (fairly important) email sent earlier this month so decided to check my postfix logs. Surprised to discover that they only go back a week and appear to being rotated daily. /etc/cron.daily/sysklogd contains the line: logs=$(syslogd-listfiles) and the output of syslogd-listfiles is: /var/log/syslog ...only. But the equivalent in cron.weekly calls "syslogd-listfiles --weekly" which *does* list the mail.* log files. So it's like the cron.daily is taking the '--weekly' output. Any pointers? No references to 'mail' in logrotate.d or logrotate.conf. It's Debian 6.0.10.