Browsing an old backup

Scenario: Old mac book Pro with Snow Leopard regualrly backed up via time machine to an apple time capsule. Recently got new MBP with Lion and would like to access some (but not all) of the files previously backed up. I know holding the 'alt' key gives me an option to 'browse other backup disks' but when I choose this, a little window pops up showing the disks available but it is empty - no timecapsule visible.

Will I have to hard wire the TC to my new Mac or is there a way to access the data via WiFi?

Any help much appreciated.

A