cat main.cf | grep mydestination
mydestination = server.ru, localhost, localhost.localdomain
proxy_read_maps = $local_recipient_maps $mydestination $virtual_alias_maps $virtual_alias_domains $sender_bcc_maps $virtual_mailbox_maps $virtual_mailbox_domains $relay_recipient_maps $relay_domains $canonical_maps $sender_canonical_maps $recipient_canonical_maps $relocated_maps $transport_maps $mynetworks $smtpd_sender_login_maps
cat mysql-virtual_mailboxes.cf
user = ispconfig
password = **********
dbname = dbispconfig
table = mail_user
select_field = CONCAT(SUBSTRING_INDEX(email,'@',-1),'/',SUBSTRING_INDEX(email,'@',1),'/')
where_field = login
additional_conditions = and postfix = 'y' and server_id = 1
hosts = 127.0.0.1
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и в бд все есть, по бд нашел что имелось в виду в админке, похоже ?
Осталось только угадать с синтаксисом ;)