update for issue 49

I'm not sure how many people have noticed, but JAXB is 
going to support 
substitution groups. Although the 1.3 developer pack 
available from
https://jaxb.dev.java.net/ says that it 
supports an experimental 
implementation, 2.0 is supposed to have full 
support. It doesn't resolve 
issue 49, but does add something to the 
discussion, i.e., it's no longer 
possible to say that no Java tools support 
it. Apparently it's on the 
Axis roadmap too.

Mark.