Seems like the transformation is direct except for the timeDate part.
Would it simplify things if we specified a backward-compatibility
convention for that? For example:
"'references' values that refer to messages in the CAP 1.0 format MUST
use a value of '2000-01-01T00:00:00' for the 'sent' time, regardless
of the actual 'sent' time of the CAP 1.0 message."
That way new references could be derived directly from the old with
no additional ambiguity, even if it isn't feasible to refer back to
the original message body.
- Art