One way to go would be to perform the backup locally (to a BKF or whatever other manner of file you will be storing it as). Then, use some combination of PGP and FTP to transfer the file over to the other server.
Some of the disadvantages of doing this would be extra processing and storage requirements (though, 300MB really isn't that much). Some of the gains would be redundancy (you'd in essence have two copies from which to attempt a restore) and a little more security (you'd be the ones holding the encryption keys, after all).
We use WS_FTP Pro here to do something similar (data transfer to vendor over the net). So far, it has worked pretty well.