I added a couple of functions to class.mailparse.php to parse the SpamAssasin boolean flag. You can then use this in pipe.php to do something different than usual (like dropping them) with mails tagged as spam.
function isSpam() {
return Mail_Parse:($this->getHeader());
}
function parseSpamAssasinFlag($header=null) {
$spam = false;
if($header) {
$spam = (strpos($header,'X-Spam-Flag: YES') !== false);
}
return $spam;
}