missing attachement file name in received message

Hello,

our partner is using Websphere to send us signed AS2 messages. He claims that he is not able to set the header of the mime part to include the filename (Content-Disposition: attachment; filename=xyz). While that is not a big problem it causes mec to display a wrong filename for the payload in the message log, namley the filename in the message header added for the signed message (smime.p7m).

That's how the message looks like (I x-ed the confidential parts):

content-transfer-encoding = binary
receipt-delivery-option = https://xxx.com/bcgreceiver/target01
recipient-address = https://xxx.com:8443/as2/HttpReceiver
host = xxx.com:8443
connection = close
date = Thu, 25 Mar 2010 14:16:45 UTC
content-type = application/pkcs7-mime; smime-type=enveloped-data; name=smime.p7m
content-disposition = attachment; filename=smime.p7m
as2-from = XXX
mime-version = 1.0
disposition-notification-options = signed-receipt-protocol=optional, pkcs7-signature; signed-receipt-micalg=optional, sha1
message-id = <1269526604717020B0000B002647266542EBABC528ADE2D@seldclue82a>
disposition-notification-to = integrationsupportA@xxx.com
content-length = 4572
as2-to = XXX
as2-version = 1.1
subject = XXX
Content-Type: multipart/signed; micalg=sha1; protocol="application/pkcs7-signature"; boundary="----=_Part_27817_1179469389.1269526604720"

------=_Part_27817_1179469389.1269526604720
Content-Type: application/octet-stream; charset=UTF8
Content-Transfer-Encoding: binary

XXX content XXX

------=_Part_27817_1179469389.1269526604720
Content-Type: application/pkcs7-signature; name=smime.p7s
Content-Transfer-Encoding: binary

0‚o’pH^Úçù(>euÒã›i㟞³ÍI?¡Ò»Z çCObH£Á
«¿§—út&”øYùàvN™E¥)ªíý§Y¬0ŒòXNÔNRpuÿºl9a
------=_Part_27817_1179469389.1269526604720--

You see there is the content-disposition = attachment; filename=smime.p7m in the header but no similar header in the part with the actual message. In my opinion mec should leave the payload unnamed in the message monitor in this case.

Thanks for your comments.
Tobias

btw: there was a related post on this topic two years ago.