Hello,
>>2. It doesn't matter which virus scanner we are using. Each user
>>(mailbox owner) must be able to disable the virus scan, otherwise it
>>would infringe German law.
>
> That's true for spam, not viruses!!!
not in all cases. Due to heuristic, there may be false positives
(especially on broken MIME parts or so). And in the end it is a
licensing issue: You have to license the scan for every mailbox, so
mailboxes not licensed cannot have a free virus scan.