Booking ferries in Okinawa

I am trying to find how to book ferries between the Okinawan islands and Kagoshima (i.e. a few in between Naha and Kagoshima and then one into Kagoshima.
Is there any English language site to do this on?
If not, what's the best option.
We fly into Naha and I want to be sure of connections before booking onward transport and accommodation when we get to "mainland" Japan.

I suggest using a Japanese speaking person to use the Japanese website - sometimes they also need a Japanese address in filling in the form. A friend is going to try making a phone booking (Japanese) and have the ticketconfirmation sent via email