Jim,
If one uses the Z-Controller and the DCS Remote Commander simultaneously, the engine will never go into reverse
Every time the Z-Controllere is turned to 0, the engine will stop. When power is turned back up via the Z-Controller, the enigma e will come up in neutral in DCS.
Then, when DIR is pressed on the DCS Remote Commander handheld, the engine will go forward. If direction is pressed on the Z-Controller, the engine will simply stutter and continue moving forward.
The two are incompatible.
Further, connecting two power sources to the same track can result in potentially very bad things happening.
I suggest that the original poster read and understand the manual that came with the DCS Remote Commander before proceeding much furthet.