[exim] Regexp for catching "prefixed" Message-ID: fields?

I took the plunge and implemented the suggestions here:

http://www.tldp.org/HOWTO/Spam-Filtering-for-MX/

-- nice work, seems to be working well overall.

However, I'd like to make use of this as well:

deny
   message     = Your message does not conform to RFC2822 standard
   log_message = missing header lines
   !hosts      = +relay_from_hosts
   !senders    = : postmaster@*
   condition   = ${if !eq {$acl_m0}{accept}{true}}
   condition   = ${if or {{!def:h_Message-ID:}\
                          {!def:h_Date:}\
                          {!def:h_Subject:}} {true}{false}}

The condition for the Message-ID: field doesn't catch things like:

X-Qmail-Scanner-Message-ID: <10953335286756398@???>

which I guess is an abomination, but let's not go there for the moment.

I'm probably looking in the wrong place in the documentation, but I
can't find if there's a way to snag "prefixed" field names like the
above. Ideally, I'd not want to write a condition for each and every
Blah-Message-ID: header encountered. Pointers would be welcome.

--

Juha