It appears I was somewhat mistaken. It's not just AUTH SSL, as I can connect with AUTH TLS as well with v2 ("FTP over TLS (explicit encryption)"). I guess something else is happening with v3 (apparently this really is a bug rather than a missing feature). As you can see from the first log (v3), it appears to be connecting, and it sends the USER command, but then it hangs. V2 has no problems in...
2007-11-15 19:56:26 UTC in FileZilla