This is the reply I got:

Because of the way the new VirusScan 9 works. VirusScan will capture the outgoing email from Outlook Express (or whatever email program you are using) scans the message and sends it. This eliminates time-out issues that used to occur with VirusScan 8. There is no way to stop the VirusScan notification that shows it is scanning an outgoing message, however, if you don't want Outbound email to be scanned, you can disable this feature. You won't be able to see the notification any longer and your outbound messages will not be scanned.

So, I made that a wish for their next version to have outbound emails to be scanned but with the ability to turn off visual notification.