[Dovecot] default_mail_env %d var problem

[pythonic]

Hello,

I am new to Dovecot and trying to setup on my Fedora Core 1 mail
servers (actually migrating from uw to dovecot ;-) ).
In my setup I use pam to authenticate virtual users.
All the usernames include @domainname in their usernames like
'jane at somevhost.com'.
Now path to user's home and INBOX includes
/home/vhosts/<domainname>/home/<username>.

I have added following to dovecot.conf.
------------------------
auth_passdb = pam
auth_verbose = yes
auth_username_chars =
default_mail_env =
mbox:/home/vhosts/%d/%h/:INBOX=/home/vhosts/%d/var/spool/mail/%n
--------------------------

Now if I try to connect imap I get foll. error.
--
imap(jane): May 19 01:58:08 Error:
mkdir_parents(/home/vhosts///home/jane//.imap/INBOX) failed:
Permission denied
--

So %h and %u looks working but not %d :(.
My pam module works right as if I use actual domain path in
dovecot.conf everything works fine. Auth works correctly with uw.

Any pointers ?

TIA,
Pythonic