I couldn't come up with a regex to catch those, but only one that would catch all other chars(as long as comments don't nest). I think you could use the following:

$test=q|\AFZ\BJK \*\AFZ...*\ |;
$new.=$1 while $test=~/([^\\]|\\\*.*?\*\\)/g;
[download]

UPDATE: Or, if comments do nest perhaps this will do:

$test=q|\AFZ\BJK \*\A\*F*\Z...*\ |;
$comment=qr/\\\*(?:[^\\]*|\\[^*]|(??{$comment}))*?\*\\/;
$new.=$1 while $test=~/([^\\]|$comment)/g;
[download]