That is, when I connect my USB drive to the Airport Extreme and mount it through the network the drive is suddenly empty. Empty as in I can't see a single file on it, but the space used/free is correct.

I thought it might have something to do with user rights and me accessing it with a set username and password on the AE, so I tried removing that and connecting with the AE's password, and that fixed it. The files on it are all a+rw, so that shouldn't be what's causing this.

Anyone have any suggestion as to what I can try to be able to use this with specified username and passwords?