Tool Ball Alignment.

I have a lazer gage fixture that I need to set-up a calibration program for. In the print there are no datum's represented, I take it it's due to having a toolball. So, how would I create an alignment for this fixture.
Fixture orientation to CMM table is tool ball is on the left side and it comes about 1.25" off the base of the fixture itself. The fixture is rectangular. I also have no CAD model.