systemd will send events to syslog. Which should write out to /var/log/..
enable in /etc/systemd/journald.conf
rsyslog appears to have a listener configured (on centos at least) in /etc/rsyslog.d/listen.conf $SystemLogSocketName /run/systemd/journal/syslog
I guess you will need to restart the service systemctl restart systemd-journald
Yes, both options are not perfect, but it seems if there is no other choice on them have to stop.
Now looking information whether it is possible simultaneously to configure logging to files (similar secure.log)