How to make an axis out of a rocker switch

[skypickle]

I read LeCuvier's wonderful pdf and in section 5.10 he discusses how to create new axis commands. Although in section 5.11 he describes how to make buttons from axes, I cannot seem to figure out how to make an axis out of switch pairs. Specifically, for the HUD brightness in the A10C_2, HUD brightness is controlled by a rocker switch.

 

clickabledata.lua has this entry

elements["PNT-BTN-UFC-INTEN-RGT"]    = default_button(_("Adjust HUD Brightness (Hold rocker)"),         devices.UFC, device_commands.Button_28, 409 )
elements["PNT-BTN-UFC-INTEN-LFT"]    = default_button(_("Adjust HUD Brightness (Hold rocker)"),         devices.UFC, device_commands.Button_29, 409, -1, {-1.0, 0.0} )

devices.lua identifies the UFC as device 8
 

so I added this line to default.lua

 

{action = 3028, cockpit_device_id = 8,  name = _('HUD Brightness Knob')},

Unfortunately, this only makes the HUD fully bright when I twist the axis all the way to the right.

Is there a better way to achieve this?