In my zimbra installation I used the command
zmprov md domain.com zimbraMailCatchAllAddress @domain.com zimbraMailCatchAllCanonicalAddress @example.com
to masquerade the internal address with the public one.
The problem is that it does it always, even when I send a mail from email@example.com to firstname.lastname@example.org.
If user2 press reply, it will send the mail to email@example.com instead of firstname.lastname@example.org.
Is there the possibility to use the masqueranding when I send mail to any domain but mail.local?