log file for window messenger

I'm sending an Instant message from IP phone via SIP proxy server to a Win
messenger & My SIP Proxy server is showing that it's getting 200OK from Win
mesenger, but I don't see any message @ win messenger. What can be the
problem & is there any mechanism thru which I can enable log file on Win
messenger to see, if any message is reaching here. plz reply back to me @
aneeraj@gmail.com