You now have a 722.3 transmission in a 190e 2.6 where previously was a 722.4.
The neutral safety switch is a very simple device. Just leave the round 722.3 one in there.

The 722.3 was never designed for the 2.6 engine. Changing the vacuum module around will not make any significant difference.

I installed a 722.3 in a W124 260e. I wasn't satisfied with the result and changed in another 722.4.

The numbers 722.3 will be stamped on the side of the transmission - although the round shaped neutral safety switch is a dead give away.