Can't find the thumbstick on VALVE INDEX controller

[HexStark]

As we all know, the Vive controller has the trackpad, and oculus has the thumbstick (joystick), and the OVRT could remapping the analog input very well.

However, VALVE INDEX controller has both of the trackpad and thumbstick (joystick).

When I use this tool, the remapping interface could only show the trackpad in both digital input and analog input, but why I can't find the thumbstick.

In openvr.h
k_EButton_Axis3 = 35,
k_EButton_IndexController_JoyStick = k_EButton_Axis3,

I also use client_commandline.exe buttonevent touchandhold 2 [1~64], the thumbstick still has no response.

Any one knows how to remapping/find the thumbstick on VALVE INDEX controller?

Thank you very much for your help!