No idea what you're talking about, but there is no "set at zero" for the VR on this radio. You leave the trigger or wheel at neutral and press the button, then move the input to the extreme ends of it's range. Then it will prompt for saving those values.

To the OP:

Does your ESC have a deadband adjustment? If you are having trouble with just neutral, you may need to widen your deadband slightly on the ESC. This gives the ESC more play around neutral to recognize the neutral trigger position.