Exchange 5.5 Tracking

[Guest_imported]

Is there a way to add a custom field, which can followed in the tracking/performance logs. We wish to track a particular type of e-mail, at present the only field we can use is the High Priority, which as you know is used by a number of internal Exchange maintenance messages.

We are willing to create custom forms if a trackable field can be logged in the tracking or any other TXT/CSV log file.