XP doesn't know whether you're using a drive tray or not in this case, it's using the SATAII protocols for hot-swaping, you can disconnect a drive in software (then unplug it) whether it's connected directly to a cable or through a drive tray.
Again I stress you have to be using SATAII for both the controller and the drive to use this included feature. Using this feature is a way around buying special "hot swap" drive racks.
<font color=blue>Only a place as big as the internet could be home to a hero as big as Crashman!</font color=blue>
<font color=red>Only a place as big as the internet could be home to an ego as large as Crashman's!</font color=red>