I'm assuming you have gotten mail to flow correctly in testing?
Did you enable report data logging under Admin, Reports, and checked off items under Email Reports Data?
Have you enabled Message Audit logging under Admin, Logs, Local. You need to do this for each scanner. I recommend Warning for all excepting Mail Transfer Agent = Information.
I'll assume you've setup your local domains under Protocols, Domains, and pointed them at your exchange box. And that on your Exchange box, you've pointed the Hub Transport at the outbound interface on the scanner(s).