[Mimedefang] SA 3.0.1 & MD 2.49 won't change the subject?

[Gerald]

After upgrading to SA 3.01 and mimedefang 2.49 I've lost the ability to
rewrite the subject line. Any suggestions on where to fix that?

if ($Domain eq "thisdomainwantsthis.com") {
	action_change_header("Subject", "*** SPAM *** $Subject");
}

Mimdefang seems to be logging that it is doing it though:
Jan 12 02:45:46 mimedefang-server sm-mta[67795]: j0C7j4d2067795:
Milter change: header  Subject: from Get a Free HP Pavillion Laptop
to *** SPAM *** Get a Free HP Pavillion Laptop

Gerald