milter-regex woes

[Christopher Martin]

I am trying to use milter-regex to pre-sort e-mail/spam before passing 
it on to clamav and spamassassin, but it doesn't seem to be working.

Here are my first, slightly lame, rules:
reject "Spam not welcome"
header /Subject:/ /\b(PHA)+([a-zA-Z]+(RMA))\b/

reject "Spam not welcome"
header /Subject:/ /\b(PHA)+([a-zA-Z]+(RMACY))\b/

discard
header /Subject:/ /TESTSTRING45819203/

I have tried sending mails with the test string (TESTSTRING45819203) but 
they get through. Are my rules wrong? I am very much a regex newbie, so 
I suspect my rules are wrong, but I need someone's help!

Thanks in advance!

Here are my various version numbers and such:

SpamAssassin version 3.1.5
 running on Perl version 5.8.8

milter-regex - CVSUP and built 25 Sep 2006