How to get MR controller thumbstick axis value?

I’m using MR headset in unreal4.16 ,how to get motionController thumbstick axis value ?I can’t find the mapping key.

A bit late but apparently the mapping input doesn’t exist in Unreal Engine yet as of 4.21.0.

This is incredibly frustrating too. It works perfectly in ‘competitor product name here’ but not in unreal. They added a secondary axis.

The WMR plug-in is also flakey. Doesn’t show controllers, if you map the standard motion controller with WMR enabled, your character slides around the scene if you implement touch-pad movement. If you use SteamVR, there is a hack to get the thumbstick to rotate the view by editing a config file. So far, that seems the best solution.