Hi javajoe,
I've read that JAX-WS can save large attachments to a temporary file on disk before streaming through to the client. It's possible that if you monitor the progress of the streaming data handler you are in fact monitoring the time it takes to copy data from local disk to another file on your local disk, which explains why it appears almost instantaneous.
I'm not exactly sure how to solve the problem but perhaps doing something with handlers (logical or message handlers - the ones that typically deal with headers) might help. Then again I'm not sure if these handlers see the message before or after attachments have been processed and saved into temporary files. MessageContext.INBOUND_MESSAGE_ATTACHMENTS might be useful.
I remember reading about Tubes a while back
(
http://weblogs.java.net/blog/jitu/archive/2007/02/tubes_in_jaxws.html).
From my understanding they have access to a whole lot of lower-level stuff that normal handlers don't. Perhaps a solution can be found there?
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