Go to the Mail tab.
Click on the email address you wish to configure the antivirus on.
Click on the Antivirus tab and select the checkbox: "Switch on antivirus protection for this email address". Choose the desired mail scanning mode. You can switch on scanning for incoming mail, outgoing mail, or both. Once the desired option is picked, click on the OK button.
Virus protection will now be set up for the selected email address. To activate the antivirus on other mailboxes, this process must be repeated, yet it is possible to select multiple mailboxes at once.