virus found in email: add tag "virus" to email subject

Hello,

I have antispam running on my Fortigate firewall. If a phishing URL is found within an email, the text "phishing" is added to the subject and the whole email is forwarded to the user. I would like to achieve the same for an email with an antivirus found.

So, if Fortigate detects a virus within an email, it should add "virus found" to the subject of the mail. I also want the whole email including the virus to be forwarded to the user. Reason: The Fortigate could be wrong. A user should still be able to decide what to do. So I will give him only a hint.

Does anyone know how to accomplish this on a Fortigate?

Regards