hey, normally I google all my problems and end up finding them myself but this time, I need your guys' help! I have an external HD that ive attached VIA usb to backup my stuff with time machine. I then got an airport extreme and attached it and everything is mounting great. But now, after selecting time machine perference to use the HD over the network for backup, time machine tries to create a BRAND new backup instead of continuing from my previous backup when I had it connected via usb... any help? thanks!