I just got an airport extreme (brand new). I have an external HDD (lacie rugged) that I use for time machine backups. I normally connect it with firewire 800 but of course AEBS doesn't have fw800 so I used the usb, It will not show up under disks under airport utilities. It works if unplug it and plug it into the usb on my mbp and does fine. So its not a usb issue or not a format issue. I turned on share disks over WAN, but still nothing. Any ideas?