dovecot 2.0.8 with postfix; transfer postfix -> dovecot by lmtp is fine

Now i have to redirect a couple of virtual email names (like admin@mydomain.com, postmaster@, webmaster@, info@, sales@ ...) to a single user postbox named xxx@mydomain. As I use mysql for the auth-sql, it's returning userhome /home/<name>/maildir for all sql requests to <name>=admin, postmaster etc. I also verified that "doveadm user info" is returning the maildir/home: /home/xxx/maildir So I assumed, that all mails to admin, postmaster etc. are transfered to user xxx mailbox. But it isn't. Dovecot is creating the maildirs /home/admin/maildir, /home/info/maildir and so on. What do I miss here to get that virtual users mapped to the correct user xxx?

Regards Birte