BMW Repair: 1991 325i Oil Pump, oil pump, oil pan

Question
I have a 1991 325i convertible that lost the timing belt.  I had to replace the head and noticed that the old head wasn't getting oil.  I dropped the oil pan and ordered a new oil pump.  I noticed that the old oil pump and the new pump only pump oil when they are rotated in the clockwise direction looking down the oil pump shaft at the pump.  I also noticed that the pump has to work in the counter-clockwise direction based on engine rotation and the gearing to the pump.  How come I can only get oil to pump in the opposite direction of normal rotation?  Every manual that I've read tells me to check the pump by rotating in a counter-clockwise direction.  I'm confused.

Answer
Hello Brad,
I understand your desire to understand what makes things tick. But have you given thought to the difference between the twist of any shaft when viewed from opposite directions? What is clockwise at the top becomes counterclockwise in the bottom or vice versa.
I think your only concern is to put in the new pump properly.And to check beforehand that the oil passages going to the head are unimpeded.
Regards,
Tino