Syslog-ng

syslog-ng is a centralized replacement for syslog that guarantees availability of logs, and is very flexible.

FreeBSD

You can not restart syslog-ng.sh in the local directory, you need to use the complete path.

# pwd
/usr/local/etc/rc.d
# ./syslog-ng.sh 
./syslog-ng.sh: Cannot determine the PREFIX
# /usr/local/etc/rc.d/syslog-ng.sh 
Usage: syslog-ng.sh {start|stop}

also make sure you do not have

syslogd_flags="-d"

still set in rc.conf or you'll be stuck in debug mode during init the next time you reboot. Remove the -d.

syslogd_program="/usr/local/sbin/syslog-ng"
syslogd_flags=""

work as of FreeBSD 5.4-RELEASE.