Actually the KB works but it's not for single event.
If this is ASP which i assume it is then you could remove the filter from signature-id and apply filter for your device id.
This way the policy for that device will be aggregation turned off.
Also by going into policy editor under Data Sources tab you can filter by device id and disable aggregation for these events in general.
Solution is tested and works.
In case that you are observing different behavior please log a case with McAfee as it might be a product problem.