Spam scanning of domain aliases

[ispconfig_question]

Hi, I'd like to ask about the Spamfilter "User / Domain" config page. I have found quite confusing information about it in ISPconfig manual (page 139 in my version). It states that domain or user aliases have to be added to this list, otherwise incoming mail to them won't be scanned for viruses/spam. I wasn't not sure if I understood it right, so I created a setup like this:
domain1.com ... mail domain in ISPconfig
user@domain1.com ... mail account in ISPconfig
domain2.com -> domain1.com ... mail domain alias in ISPconfig
Then I sent two mails, one for user@domain1.com and the other for user@domain2.com. If I understand the part of manual right, the second one is supposed not to be scanned. But both have been delivered with the same X-Virus-Scanned in headers.
Then I checked the User / Domain page in ISPconfig and it seems both domains are listed there (I havent added them).

So did I get the manual wrong? Do I need to add domain/user aliases to User / Domain list or not?

Thank you for any explanation.

[till]

If you select a spamfilter level in ispconfig, then the domain gets added to the spamfilter domains automatically.

Beside that, the x-scanned header is always in the email as the spam filter setting defines the rules snd levels that get applied to the email. So you can not use this heder as sign which rule was applied to this specific email.

[ispconfig_question]

Thank you for reply. Now I get it - to be able to add domain as an alias, I have to add it as a mail domain first, which adds it to the User / Domain list. The info in the manual is maybe a bit confusing, but I think I understand it now.
Thanks.