/home/(USER_NAME)/fml/spool/ml/(ML_NAME)/
にあるconfig.phに以下の記述を追加。

# YOU CAN EDIT MANUALLY AFTER HERE.

$USE_ORIGINAL_MESSAGE_ID = 0;

$SKIP_FIELDS = "Received|Return-Receipt-To|DKIM-Signature|X-Google-DKIM-Signature|X-Gm-Message-State
|X-Google-Smtp-Source|X-Received";

$SMTP_OPEN_HOOK = q#
     $Envelope{'fh:reply-to:'} = $MAIL_LIST;
     $header_from = $Envelope{"h:From:"};
     $header_from =~ s/\/\)/g;
     $header_from =~ s/\"//g;
     $header_from =~ s/^\s+//;
     $header_from =~ s/\s+$//;
     $Envelope{'fh:from:'} = "\"" . $header_from . "\"<" . $MAIL_LIST . ">";
#;

@DenyProcedure =

その後、

perl -c config.ph

を実行して

config.ph syntax OK

となればOK。