Daniel, just to be clear, you are saying that 100% you have tested this and got it working with a trigger box?
The diagram shows the coil having a single winding with both leads floated. The red and white are the two legs of the coil. Grounding the white makes it like any other single lead coil, they just choose to float it either maybe for lights on some models? Or just for reliability.
The pietcard coils have two windings that are both grounded to the frame of the coil... I know this for a fact, one winding is the power winding and one winding is the trigger winding and if you get lucky it just kinda happens to work with a 2 magnet flywheel.