Scriptaculous usage questions

Hi,

I have a little problem I would ideally like to solve without writing
a single line of Javascript, but I wonder whether that's possible at
the moment.

I have a form that needs to do two things:
- When a field changes, post an identifier, the field name, and the
value (using XMLHttpRequest).
- For any given form, an update loop that, via XMLHttpRequest, post an
identifier and reads back field name and value. This request may not
return immediately.
Together, with some "magic" inside the appserver, this would result in
keeping two copies of the same form synchronized. The server blocks
the request from the update loop, and continues that request as soon
as the other copy of the form posts a change. The identifier
identifies a 'synchronization session', e.g. two people looking at the
same data.

(background: we want a callcenter agent to help a customer with
filling in forms).

Now, this is easy to whip up with HV2 and plain Javascript using any
run-of-the-mill XMLHttpRequest wrapper. I just wonder how this would
be done cleanly inside Seaside, using Scriptaculous, and avoiding
handcoded Javascript larding my Smalltalk code :-).

(one issue I already encountered is that Seaside sessions serialize
requests - so the blocking update poll request blocks out anything
else in that session, meaning that this thing needs to run in its own
session, probably).

TIA,

Cees