[Mimedefang] differing spamassassin configs

[John Nemeth]

     I've started looking at scanning outbound mail for spam.  This
is to prevent being added to RBLs.  As part of this, I would like
to be able to call spamassassin with different settings.  All
outbound mail is either coming from the same system or authenticated
users, so when scanning outbound mail I don't want any RBLs being
consulted.  However, I still want RBLs to be consulted for inbound
mail.  I've looked at mimedefang.pl and don't see any easy way to
do this.  The only obvious thing is to set $SASpamTester to undef
before each call to spamassassin.  I'm wondering if a destructor
function should be called or if this would result in a memory leak.
Does anybody have any other suggestions?