No headers in EDIINT MDN messages after upgrade 61 to 65

I’ve been sending XML content using EDIINT AS2 and receiving EDIINT MDN messages for some time. This week, I upgraded our server from 6.1 to 6.5 (with EDI Module SP1). After that, the messages still go through, but the MDNs come back as document type “EDIINT” with “Unknown” sender and receiver (instead of type “EDIINT MDN” and identified sender/receiver). Looking that the MDN message’s content, the headers are missing.

In 6.1, the EDIINT MDN messages look like this (content type is multipart/report):
Date: Fri, 11 Nov 2005 02:20:45 GMT
From: MDN_sender_ID
AS2-Version: 1.1
AS2-From: MDN_sender_ID
AS2-To: my_ID
Subject: my_ID;MDN_sender_ID
Message-Id: <200511101920459A4BFCCB@MDN_sender_ID>
Content-Type: multipart/report; report-type=“disposition-notification”; boundary=“iSoft2BounDary2iSoft”
Content-Disposition: attachment; filename=“my_ID.MDN_sender_ID.mdn.200511101920456392F69346E.out”
Content-Length: 588

–iSoft2BounDary2iSoft
Content-Type: text/plain

Message <312905086.1131675644314.JavaMail.ZSVCWebMethods@my-wm-server> was successfully preprocessed.
A total of 10055 bytes were received.

–iSoft2BounDary2iSoft
Content-Type: message/disposition-notification
Content-Disposition: attachment; filename=“mdn.txt”

Reporting-UA: iSoft Commerce Suite Server
Final-Recipient: rfc822; MDN_sender_ID
Original-Message-Id: <312905086.1131675644314.JavaMail.ZSVCWebMethods@my-wm-server>
Disposition: automatic-action/MDN-sent-automatically; processed

–iSoft2BounDary2iSoft–

After the upgrade, they look like this (content type is application/pkcs7-mime):

–iSoft2BounDary2iSoft
Content-Type: text/plain

Message <365477901.1132107654607.JavaMail.ZSVCWebMethods@my-wm-server> was successfully preprocessed.
A total of 11307 bytes were received.

–iSoft2BounDary2iSoft
Content-Type: message/disposition-notification
Content-Disposition: attachment; filename=“mdn.txt”

Reporting-UA: iSoft Commerce Suite Server
Final-Recipient: rfc822; MDN_sender_ID
Original-Message-Id: <365477901.1132107654607.JavaMail.ZSVCWebMethods@my-wm-server>
Disposition: automatic-action/MDN-sent-automatically; processed

–iSoft2BounDary2iSoft–

Any help would be greatly appreciated!