Cyberduck won't work as far as I can tell. You can use Fugu or any other FTP program that allows you to "Force SSH1 connection." If you use Fugu, you'll see the Force SSH1 connection as an option below the username/password fields. Works like a charm.
You may have to go in at least once with Terminal in order to get past the
The authenticity of host '<whatever yours is>' can't be established.
RSA key fingerprint is 70:09:e8:69:57:31:75:66:0b:90:f6:bb:73:67:b7:9c.
Are you sure you want to continue connecting (yes/no)?
first run stuff. Answer yes there and your SFTP programs might work better.
Keep in mind, too, that after an ATV update, things are going to change, most likely, so you may have to remove your previous entry in ~/.ssh/known_hosts to allow even that step to pass cleanly.
Once mine is all set, I use sshfs to mount the frontrow user partition in Finder. Then I can just use Finder to Drag-N-Drop stuff there. In order to use it, you have to first install the
MacFuse core stuff, and I think you can get to "sshfs" app from there (unless it installs with it, I don't remember).
You also have "MacFusion" available, which works out of a menu when the dust settles, and adds even more features (auto mount, etc...), but I haven't had as much luck with that for some reason.