Re: Representation header

I have a vague intuition that some of the metadata we might want to carry 
is specific to the "Representation" header, but others might be applicable 
to a broader range of MTOM content.  For example, just because my binary 
is an image/jpeg doesn't mean I should need to claim that it's a cached 
copy of some particular URI.  So, I'd claim we want to allow media type 
annontation on most any child element that's base64Binary.  Perhaps the 
same for some others such as content-encoding, content-language, etc.  On 
the other hand, I would think that the URI being cached is pertinent only 
to the Representation header.  So:  would it be worth a bit of energy to 
sort out which things apply only to Representation and which to a broader 
range of MTOM content. 

BTW:  It's really too bad that XML doesn't have structured attributes, as 
many of the MIME headers would seem to fit nicely as structured attributes 
on the corresponding base64Binary representation of the content.

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Noah Mendelsohn 
IBM Corporation
One Rogers Street
Cambridge, MA 02142
1-617-693-4036
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