ok. i might have som high end Pepperl+Fuchs sensors laying in a drawer somewhere, i will get back to you with the specs of them.
is the voltage spesific to 12V and 24V? is that because of the inputs? (that means i need to get yet another powersuply.. 24v is commonly available in industry tho)
Yes you should have a separate, isolated 12V or 24V power supply for all your limits, home, and other switch type inputs. The 16 opto isolated inputs on KSTEP all have the same common anode so they basically must all operate from the same voltage (12 ~ 24V) and be NPN type to sink current to GND.

one strange thing i noticed is that my 5V output from the KFlop is more like 4.4V (JP4 pin 1 and 8)
If you are only supplying 4.4V to KFLOP that is not good.

Start and Stop (according to the manual it should be a matter of shorting pin 4 (s/p) to pin 7 (GND) contact means start)
Clockwise and Counterclockwise rotation control (5 (F/R) "Forward running on High level, reverse running on lower level" (guess shorted to 7 (GND) means forward)
KSTEP has two "Relay Drive Outputs" that should work for this purpose. They basically work like switches. The next step would be to get those working. See the section on "Relay Driver Outputs" in these two KSTEP Help Pages:

KStep Connectors
Using KStep

Regards