I am having problems with any of my external USB hard drives showing up in the Airport Utility program of my Airport Extreme. All three of them work fine when connected to the Mac normally. When plugged into the router, two of them don't do anything at all and the third starts the light flashing amber. Again, none of them over show up in the disk list. I've searched the forums here and elsewhere and can't find an answer. My hope was to have these drives up on a hub as network storage. My printer works fine as a network printer through the router. Thanks.