Have you posted this in the Enterasys community as well? I know there are many McAfee users who use the notification features of NAC. https://community.enterasys.com/enterasys But, the notification engine for NAC is located here https://extranet.enterasys.com/downloads/Pages/dms.ashx?download=3d7a3934-ce85-4 edc-8792-6e9ca9c22d9b starting on page 369. That should get you going for sending events. If the events are still not sending, give our GTAC a call and we should be able to solve the issue. Thanks!
Have you setup your Enterasys NAC as a Data Source on an Event Receiver and Enabled Parsing?
Looks like "Enterasys Network Access Control (ASP)" is a Data Source Model for that Data Source Vendor.
I would set the "Support Generic Syslogs" to (Log "unknown syslog" events) so you know for sure if you are receiving events that for some reason are not being parsed properly.