SuperDuper doesn't "see" mounted volume over Airport

[crabwalk]

I've been using SuperDuper happily for a while to back up my Power Mac G5's two internal drives to Firewire drives. It's served me very well.

But today I wanted to use it to copy my Mail.app mail and settings over to my laptop. (I'd always copied them over manually, but I'd rather be able to smart update them back and forth when I go out of town and use my laptop for extended periods.)

The problem was that SuperDuper didn't "see" my laptop. That is, it never showed up in the pulldown menus that indicate the copy source and target. This despite the fact the laptop's drive was mounted (via Airport) and sitting right on the desktop of my G5.

Is there something I'm doing wrong? SuperDuper automatically sees my external Firewire drives as soon as they're connected and mounted, but for some reason it couldn't see my laptop over Airport, despite multiple attempts. Ideas?

Josh