dovecot - May 2009 - A few easy pam and virtual domains questions

I am using dovecot with postfix, which was setup to do virtual
domains. Dovecot is setup to authenticate against pam (I know, I know)
and knows to look for email in /var/spool/vmail/:

virtual_mailbox_base = /var/spool/vmail

I also have virtual_mailbox_maps defined as

virtual_mailbox_maps = hash:/etc/postfix/vmaps.txt

where I currently only have one account,

% cat /etc/postfix/vmaps.txt
raub at domain.com domain.com/raub/
%

Inside raub we have the usual 3 directories, new,cur, and tmp. When I
try to login through imap as raub at domain.com@mail.domain.com (i.e.
since we are doing the virtual domain thingie, the username has to
indicate the domain it belongs to), it will not take it. But, if I
login as raub at mail.domain.com, it has no problems authenticating.
However, it now expects to retrieve email from /var/spool/vmail/raub
instead of /var/spool/vmail/domain.com/raub. Why would it be doing
that? Could it be that pam reports raub to be a local account and as a
result simply ignoring vmaps.txt?

I asked dovecot to log everything it could. When I checked the log
file, the following line screamed at me:

dovecot: May 27 14:40:28 Info: IMAP(raub): maildir++:
root=/var/spool/vmail//raub, index=, control=,
inbox=/var/spool/vmail//raub

Note the "//" in root and inbox declarations; between those slashes I
would expect to be domain.com.

Compounding the problem, and perhaps a clue of how pam is telling what
these accounts are, postfix is completely ignoring /var/spool/vmail,
placing the emails in /home/raub/Maildir (account is actually being
nfs-automounted and user authenticated through ldap through pam). Once
again I am guessing it too is being told raub is a local user; am I
correct?

Something I forgot to mention: when I first connected to the
mail server as raub using imap, dovecot created a few files. No
problem with that. But they were owned by the user raub,

raub at mail $ ls -la /var/spool/vmail/flingingmonkey.com/raub
total 32
drwxrwxrwx 5 virtual  virtual 4096 May 26 16:23 .
drwxr-xr-x 4 virtual  virtual 4096 May 21 11:34 ..
drwxrwxrwx 2 virtual  virtual 4096 May 21 11:34 cur
-rw------- 1 raub users     17 May 26 16:23 dovecot-uidlist
-rw------- 1 raub users      8 May 26 16:23 dovecot-uidvalidity
-rw------- 1 raub users      0 May 26 16:23 dovecot-uidvalidity.4a1c4fa9
-rw------- 1 raub users    140 May 26 16:23 dovecot.index.log
drwxrwxrwx 2 virtual  virtual 4096 May 21 11:35 new
drwxrwxrwx 2 virtual  virtual 4096 May 26 16:23 tmp
raub at mail $

instead of user virtual, which is the account I have to own
/var/spool/vmail and is known to dovecot as

virtual_uid_maps = static:1500
virtual_gid_maps = static:1500

Why is it doing that? Is that another clue that it think raub is a
local user due to it being authenticated through pam?