Darn what a pain to remove. Definitely not seen anything here like that pump. It looks like you have to disassemble the whole pump just to get to the crankshaft screw holding the pump on.

But is the IPL.

http://www.kewparts.com/uploads/2/7/2/3/2723556/03kb.pdf

IF you look on PDF page 8 you'll see item 37 is what holding it on to the crankshaft even the parts list is calling it a set screw.