[Mailman-Users] How to hold missing subject line

[patrick king]

I need to use the administrator's GUI to construct a regular 
expression.  The expression needs to hold posts which do not contain 
a subject line in the header.  In other words, the Subject: line is 
entirely missing from the mail header.  It is not that "Subject:" is 
present with data missing after it. 

Any ideas?

I have spend a day trying everything I can think of doing. I have 
searched the procmailex man pages, the user & list manager 
documentation, FAQ pages, and the message archives for this list 
(regexp).

I use Mailman 2.0.13 with Pipermail 0.05 (Mailman edition)