As long as you have a backup device plugged into the USB port then you can do a full backup that can be used to restore the box.
If the H2 is connected to your LAN then all files can be accesses over the network without using FTP
In answer to your last Query there is no way to edit the files in /usr/keys without the use of a Laptop/PC you need to either use an appropriate FTP program or set up the NFS share so that the receiver becomes viewable on the network