JES5: outlook shows 'fake' attachment icon for mails originating from uwc/explorer

Hi,

Strange thing:

We are using JES5 with both UWC and outlook connector.

Mails sent from UWC in Internet explorer (dutch version) display a 'file 
attachment' icon in outlook 2003 (in the header pane). In the message 
pane, there's no file attachment.
Mails sent from UWC in Mozilla (dutch version) display fine in outlook 
2003 (that is: no sign of a file attachment icon).

Upon further inspection, I noticed that Internet explorer generates this 
type of mime header (notice the multipart/mixed)


X-Mailer: Sun Java(tm) System Messenger Express 6.3-4.01 (built Aug 32007;
 32bit)
MIME-version: 1.0
Content-language: nl
Subject: test tekst
X-Accept-Language: nl
Priority: normal
Content-type: multipart/mixed; boundary=--30a08e3d58b82ed92965
X-ESAFE-STATUS: Mail clean
X-ESAFE-DETAILS:

This is a multi-part message in MIME format.

----30a08e3d58b82ed92965
Content-Type: text/plain;
        charset=us-ascii
Content-Disposition: inline
Content-Transfer-Encoding: 7bit

testtekst


----30a08e3d58b82ed92965--


Mozilla generates this type of mime header (ntocie the 
multipart/alternative)

X-Mailer: Sun Java(tm) System Messenger Express 6.3-4.01 (built Aug 32007;
 32bit)
MIME-version: 1.0
Content-language: nl
Subject: test vanuit nl - uwc - html
X-Accept-Language: nl
Priority: normal
Content-type: multipart/alternative; boundary=--3091e7cf67b73e73237c
X-ESAFE-STATUS: Mail clean
X-ESAFE-DETAILS:

This is a multi-part message in MIME format.

----3091e7cf67b73e73237c
Content-Type: text/plain;
        charset=us-ascii
Content-Disposition: inline
Content-Transfer-Encoding: 7bit

test test

----3091e7cf67b73e73237c
Content-Type: text/html;
        charset=us-ascii
Content-Disposition: inline
Content-Transfer-Encoding: 7bit

test test

----3091e7cf67b73e73237c--


This (cosmetic) problem is unrelated to choosing 'pure text' or 'html 
text' in the UWC message creation window.


I don't know where to look for solving this bug:


- is it outlook that is unable to correctly parse the 'multipart/mixed' 
type of mail ?
- or should internet explorer generate multipart/alternative style mails ?


any ideas ?


gr,
Tom.