[exim] Urgend unpacking proiblem

Hi

I do have some mails waiting at another companies mailserver for delivery to
our exim system.
My problem is, that this is a mail of about 7mb, which consists only of a
delivery failure message with an attachment, which consists only of a
delivery failure message with an attachment, which consists only of a
delivery failure message with an attachment, which consists only of a
delivery failure message with an attachment, which consists only of a
delivery failure message with an attachment, which consists only of a
delivery failure message with an attachment, which ....

So, exiscan takes a while for unwrapping this. Basically about 5 threads of
that take our server down.

So I want to disable unpacking (and hence mime checking as well as virus
scanning) for these particular mails. However the only common point I know
in advance is the mail adress.

Here is what I tried so far:

acl_data:
  accept  condition      = ${if match {$recipients}{user\@domain.de} {1}{0}
}

  accept  condition      = ${if match {$recipients}{user2\@domain.de} {1}{0}
}

  warn    condition      = ${if !def:h_Message-ID: {1}}
          message        = Message-ID: <E$message_id@$primary_hostname>

  deny    message        = Sorry, this mail has illegal mime encodings:
$demime_reason
          demime         = *
          condition      = ${if >{$demime_errorlevel}{1}{1}{0}}

  deny    message        = Sorry, malware detected ($malware_name)
          malware        = *

But this does not work.
Exiscan tries to unpack again.

Any urgend help would be appreciated, since this is taking down our server
over and over.

Regards,
Steffen