Please can you tell me how i can access the exchange module to enable me to run a scan on public folders and the message store? I can't find any menu for exchange options.
This is not possible. It's simply not supported by the Exchange system - so practically no antivirus has this feature... On the other hand, the Exchange Information Store
automatically performs scan of
all items after AV installation and also after each VPS update (unless this feature is turned off). This is called 'Background scanning' in Exchange parlance. This feature more or less ensures that there are no viruses in the store, at any time. So you shouldn't really have a need to perfom any on-demand scans - the cleanness of the store is ensured automatically (even for the items received prior to the AV scanner installtion).
Also how can i test it is functioning correctly?
Well - classic methods -- eicar, or wait for a couple of minutes -- for the next arrival of a Beagle, MyDoom or Netsky variant...

Cheers,
Vlk