As nobody replied - i thought i'd reformat the problem a bit to make
things clearer :-)

Question : Is there a a way to implement Instant Notifications using
the
new messaging features of WSE 2.0 ?

Idea is to send a message to a winforms app on a client machine from a
web service.

As a start i think this would be possible setting up a TCP listener on
Client Machine Winforms Application.
soap.tcp://IPADresss/SoapService

And then sending a message from the Web Service to this Listener.

Question is - How do i find out the IP address of the Client at the
first place ?
I was conidering the possiblity of finding the IP address of the
client
using WMI .

However the situation would be complex in the case of a machine behind
a proxy. Maybe we can find out the IP address of the Client machine
from Soap
request?

Question : Is there any other way of sending a message to a client
asynchronously using web services?

I'll try and put up a Version 3 of this question if it still isnt
clear