procmail forwarding: messages getting lost

hi all!

(My system is: Debian/postfix/procmail/spamassassin;
the configuration of postfix and procmail are quite close to the
default one (at least, as provided by current Debian "testing"
distribution))

The problem is as follows: there is a user -- foo@domainA.com. His
..procmailrc looks like this:


MAILDIR=$HOME/Maildir/new
DEFAULT=$MAILDIR
LOGFILE=$HOME/procmail.log
LOGABSTRACT=all

:0:
! foo@domainB.com


(plain forwarding)
Another user, bar@domainA.com sends a letter to foo@domainA.com. The
message passes well through procmail's forwarding, but then is lost (!)
(The addressee does not receive it anyway).
In this case, the only thing I see in logs is that the message is
delivered to procmail, and then removed from the queue. like that:


Nov 16 14:57:36 xs335 postfix/qmgr[24215]: 572E426ECA1:
from=, size=390, nrcpt=1 (queue active)
Nov 16 14:57:36 xs335 postfix/local[14719]: 572E426ECA1:
to=, relay=local, delay=0, status=sent (delivered to
command: IFS=' ' && exec /usr/bin/procmail || exit 75 #foo)
Nov 16 14:57:36 xs335 postfix/qmgr[24215]: 572E426ECA1: removed


BUT!: If forwarding is avoided, and the message is sent directly (from
foo@domainA.com to bar@domainB.com) -- the message is successfully
delivered (!!!) (I clearly see the response of the remote SMTP server,
and the addressee is satisfied).

Note: Users _must_ be unaware of any changes within the server. I am
absolutely not able to tell foo@domainA.com to send messages to
bar@domainB.com instead of bar@domainA.com .

So, the questions:
- What I'd like to see is the remote (domainB.com's) SMTP server's
response (is the message "accepted"?). man procmail* do not let me see
the secrets of procmail's forwarding mechanism. Logs don't show
anything either. procmail's verbose mode is neither of any use.
- What is the destiny of the lost messages? Where are they?
- Is there a possibility to control the procmail's forwarding?
- Is there an alternative for procmail?
- What is the way-out?

(Thanks in advance :])

Sincerely,
K.Gruzdnev