They could be made to work together, however I'm sure the Novamill original logic wiring voltage was 12V, and the smartstep board dropped it to 5V for the motion controller, which is why it's a relatively simple job to interface the smartstep to a parallel port.

To use a CS-Labs controller, you would have to swap the logic wiring to 24V, and wire it directly to the CS-Labs unit, and only keep the step/dir signals connected to the Smartstep.