Shoutbox

You can't just "change" a program like this. The web messenger will more than likely be running as an Javascript interface to a server that relays standard messages to and from other WLM accounts. As far as I know it has no features of WLM and is no better than using an alternative client.

If WLM and Skype protocols are running side by side in the Skype client, some server has still got to be hosting it (to an extent; it more than likely relies on establishing a direct IP connection). That is the route I would go down personally, although I know first hand how complicated the protocol gets (I'm talking about MSNP8; we're on at least MSNP15 now).

IIRC WLM let you set proxy settings? A chinese proxy should do the trick without needing a chinese client. (Server thinks you are in china, could be travelling... therefore need access to the service)

AFAIK, all clients, versions, protocols etc use the same server and port (messenger.hotmail.com:1863). I think they will somehow restrict traffic through the gateway server; meaning the service will still be there, but inaccessible. This would be easiest to do by blocking IP ranges (why a proxy might work). I think MS would expect people to try this though and take other factors into consideration (In this situation I would personally look in to ping times; if ping>x ms then you are not really from China; I'm sure they'd be more refined than this though)