Virtual UIDs and delivery error

Hi!
I managed to combine Postfix with PostgreSQL.
It works in that way, that Postifx reads data from the pgsql db
but..
When it comes to delivery by virtual agent the log says:
mailbox ///home/tech/Maildir/: cannot open file: permission denied.

Now. In the db address tech@kluska.info has an uid and gid
set to 5000. My domain is nucleus.net (internal)
and user tech locally has uid 1001. Of course I could set
uid/gid in the DB to right values but what happens when:
admin@kluska.info is root@nucleus.net?
One cannot set an uid/gid to 0 in the DB since minimum
virtual_minimum_uid is 1!

My first thought was that virtual agent runs with root privileges
but then I read in man that it switches to UID retrieved from DB
at delivery.

Can anyone help?

PS. Sorry for my bad english..

Regards,
--
Marcin "Dentharg" Gil
RLU# 221865 :: email# mgil (at) vernet pl
G-G# 185057 :: JID# dentharg (at) chrome pl