lua custom keybinding, decrease knob value_down by 0.1

Hi, I'm testing around keybindings on my throttle to control the Airplane interior lights (in my case instrument lights on the Harrier)

I can easily define two buttons to turn instrumental light on/off setting the value_down to 0.0 or 1.0, eg:

...., value_down = 0.0, ...

...., value_down = 1.0, ...

but I'd like to use a button to DECREASE the current value by 0.1

so instead of turning it OFF, it'd just decrease the brightness

eg:

starting from 1.0 (full brightness)

press > 0.9

press again > 0.8

press again > 0.7

...

is this possible in joystick.lua scripting?

thanks

Hey dude, sorry I do not have your answer but I would love to know how you can set controls to change arg values like you have done in your post. Any help is appreciated thanks!