[Yosemite Sam]

Some years ago I was faced with the same problem. As far as I know there is not an adapter made to get around the starter pulley.

I ended up using a Lovejoy coupling and building a very simple bracket to hold the pump. I know this isn't exactly what you wanted to hear, but the Lovejoy couplings really are pretty strong and best of all they are very forgiving if your alignment isn't just perfect.

I've been using my splitter for a number of years now and have never had any kind of pump/bracket/coupling related problem.

Good luck with your project.