Ok, so much for the easy questions..
In your m4 source file add 'define(`confMILTER_LOG_LEVEL', 14)dnl', rebuild and restart. If that doesn't start logging a pile of stuff on mail receipt preface it with 'define(`confLOG_LEVEL', `14')dnl' for general sendmail logging and rebuild/restart again.Have you tried bumping the log level of sendmail?No, what would be the appropriate way of doing that? It's been a few years since I've worked with sendmail extensively.
-dg-