Adding an airport extreme base station so I can connect an aftermarket backup disk to the network to be used by Time Machine.
From what I understand uverse needs their router used instead of any other. So I think you will have to put the AEBS into bridge mode and not have it working as a router. It should still serve up the hard drive as a time capsule, it just won't be doing the DHCP or DNS work for your network. The uverse router will be fulfilling that role.