Graeme,
I think that 'id-data' covers any MIME object, not just
CMS. Since it's defined in the S/MIME standards, the door
is certainly open for somebody to question the scope of its
use as a generally applicable identifier for all
MIME. However, since (to my knowledge) nothing like this
exists elsewhere, it's the best choice available.
OK - that's good - that's clarified it for me.
I'm not sure if this could be commented on in the draft, maybe
in the context of carrying multipart/signed?
If so, something like:
"If a multipart/signed message is to be transported in X.400, the
CMS-defined
value id-data SHOULD be used in the content-type field of the P1 envelope."
after the definition of id-data in section 2.2?
However, you may not want to do this if the draft is just looking
at transporting CMS objects, or do want start down the road of
addressing transporting generic MIME in this draft.
Graeme