i figured it out
i had to un-comment the submission port
and add the port to the ispconfig firewall.
that enabled it.
i also came across another error after i got it working,
about the file-system when the email client connected.
i installed the gamin library
apt-get install gamin
then i restarted courier services:
find /etc/init.d/ | grep courier | while read line; do $line restart; done
and the error went away.
thanks for your quick reply falko.