I moved your question to the AppMon forum.
Your only option in this area is a custom plugin and if the existing one you've tried doesn't suit your needs the only option would be modifying it or creating your own. AppMon does not have the ability to monitor your logs on it's own. I'm not aware of any other suitable plugins.
Also note that if you're using a log plugin currently it is not one that is out of the box, the only one I'm aware of is a community plugin.