Signed MDN's and Unix mail agents

["Graham helliar, http://www.Digital.com/info/edi" <helliar@xxxxxxxxxxxxxxxxxxx>]

Hi,

During the EDI Pilot testing we have found that the signed MDN coming in to a 
Unix system can get 'altered'. In particular, I receive a multipart/signed where 
the first bodypart of the multipart/signed is the multpart/report containing the 
MDN. My test partner included the headers to my original message (minus the 
colons) in the third bodypart of this MDN to add content to what the MDN was 
referring to. So, it included the line:

>From graham.helliar@xxxxxxxxxxxxxxxxxxx

Unfortunately, by the time this mail reaches me, this line has become

>From graham.helliar@xxxxxxxxxxxxxxxxxxx

Note the inclusion of the angle bracket. It appears this is a 'known feature' of 
'semdmail' on Unix systems. 

Needless to say this is disasterous as altering the data invalidates the 
signature. Any comments, as we seem to have a serious flaw here when talking to 
Unix boxes!

Graham