[Vive] How to get DPad button press

I'm trying to access the DPad (circle) button events on the wand, using

wandLeft.Device.GetPress(EVRButtonId.k_EButton_DPad_Up)

But it doesn't seem to respond to presses (k_EButton_SteamVR_Trigger works fine).

Does anyone know the proper way of accessing DPad input? As the enum value doesn't seem to do anything currently.