Reenumeration of USB device does not work properly

Hi all

I have a problem in reenumerating USB device with out unplugging it . I have
used the devcon example and also the article
http://support.microsoft.com/default.aspx?scid=kb;EN-US;Q259697
. Both of them did not work the way expected .

The problem is like this , Initially the device is loaded with one VID and
PID and a seperate driver for it, later when I scan for new hardware again ,
though I am sending a different VID and PID in the Descriptors from the
Device , still it loads the old driver which is associated with old VID and
PID . This problem does not occur when I unplug the device and replug it.

Can anybody tell what is the problem here . Am I missing something in the
implementation ?

Thanks in advance
srinivasa