Virtual domain

Hi all..

I've a question about virtual domain.
On my mta i've a virtual domain file... all works fine... messages are
delivered, but i saw in my maillog that when postfix deliver the messages to
virtual user (like user@virtual.domain.com), it writes user@my.hostname.com
where my.hostname.com is the mta fqdn domain name. So all af my virtual
users are aures@my.hostanme.com in maillog like my virtual user and my
virtual domain are local users and local domain. In fact my Vexira antivirus
scans email for all of my users even if they are not included in domain
license file.
By what depends???
I use Postfix 1.1.12 + Courier imap/pop3 + Vexira + Spamassassin.



Thanks