Hi,
I have helped a few customers interface our controls to the old Ah-ha drive boxes. All you need to do is make a crossover cable from their (I think DB37) to a DB25. I just did it with 2 connectors and soldered wires in between. Attached is a simple doc that I made a few years ago when I set one up. There are 2 pins that need to be jumper-ed for enable, and they are not on this doc so you will need to look them up. Or you could just make a cable and connect the DB37 to a BOB.
Andrew
PS. I just realized the PDF only shows the connections I made to the PPort. So it really doesn't help you. But I do know it can be done, I just don't have a document on it any more. From what I remember all the IO is 5V and it uses standard Step and Dir.