Currently mediaservers offering DAAP or the generic RSP service will only work within the local subnet. This is because the multicast packets for the discovery are not routable.
The current way to circumvent this is to use VPN or ssh-tunnels, which works when one wants to connect via a computer to a remote DAAP or RSP mediaserver. This does not work from a SoundBridge as one cannot start a VPN or tunnel from it.
The only other way is running RendezvousProxy. But it requires a running computer in the same subnet as the Roku.
However it appears that the fireflymediaserver has no remote limitation like iTunes v>4.0, so all that should be required in the roku is a software update to allow discovery of DAAP and/or RSP mediaservers not only via the broadcast rendevous method from Apple but also from a manually entered IP/DNS:port location.
Please note that the problems which lead to Apples decision to turn this off in their software are nonexistant for the roku SoundBridges. It would be suficient if this was limited to a single manual discovery location.
This would be nice for all people running Rokus is more than one houshold as well as anyone using a router which doesnt bridge the multicast packets or who uses generally a more complicated network topology.
We have someone coming with these problems to this forum at least once a week and currently we send em home to change their network or buy a new router.