Help !, WebCam Problem in MSN Messenger 6.1

Dear All,

I write a webcam driver in WinXp, and I had some problems
when I use it in 'MSN6.1. 'MSN6.1' can detect the webcam
and it works well after I plug my webcam at the first
time. The problem is 'MSN6.1' can not detect the webcam
after I unplug and plug my webcam, but webcam setting
in 'MSN6.1' is OK. I can see the video in webcam setting
in 'MSN6.1'. The webcam will be detected in MSN6.1 after
2 minutes or more, and then it works OK. The webcam
driver I wrote is stream minidriver, not using USBCAMD.
Could you give me any clues about this? Thank you.

Peter