what usedid is used by doveadm for creating mailboxes? can it be setup to run as dovecot:mail?

cant create mailbox from command line ponto# ls -ld /var/mail drwxrwxr-x 8 root mail 24 Apr 5 20:35 /var/mail

ponto# doveadm mailbox create -u jboss INBOX doveadm(jboss): Error: Can't create mailbox INBOX: Permission denied

mail_location = maildir:%h/Maildir:INBOX=/var/mail/%u