[syslog-ng] convert logoutput to syslog

We use a commercial content management system that does not log to syslog but has its own log files. I can however modify where the log files are written via a config file directive. I'm interested in writing (or acquiring) a small program to convert the proprietary log output to something more syslog-ng like and redirect the stream to syslog-ng. I could probably use the logger command to accomplish the latter but how to convert the log output to use syslog facilities is the real question. Any advice, has anyone done something like this before? Thanks, -Mark