[Dovecot] Grant access for Unix-User _and_ virtual Users

[marco]

Hi group,

I have installed a postfix as an MTA and configured two "main" domains 
as well as two virtual mailbox domains. Normal unix users have their 
maildir in their homes (/home/%u) and the virtual mailboxes are located 
in /var/mail/vhosts. It works well, I only have a problem configuring 
dovecot.
I wondered if it's possible to configure it in a way that both, unix 
users and virtual users, can access their mailboxes. I found some 
tutorials but they either give access to the "normal" unix users or to 
virtual users who are defined in a text file.

Here some system infos:
- Ubuntu 12.04.2 LTS (Kernel Version: 3.2.0-23)
- Dovecot Version: 2.0.19

Hope you understand my problem.

Cheers, Marco

PS: It's the very first time I use a mailing list, so I hope you can 
forgive me possible beginner's mistakes.