Thanks, Richard and gnaget. In the end, I went to Haneda the night before and hung out in the lounge. I had some work to get caught up on anyway, and it just helped me sleep better on the flight.

I had gone to the pickup point for the Haneda buses (stop 24) and the only people around there were the luggage porters. There was a telephone number, but I figured the chances of my language working on the call were slim. I did not look for a ticket office - I'll check that out the next time I am in Shinjuku.

Thanks again!