Basically Soft Keys

this mod injects into minecraft input utils, and allows it to properly use virtual keys, sent by programs like LuaMacros

this allows you to use keys from f13 to f25 as additional binds for a USB numpad, or any other extra keyboard you might have
##
it should work fine with any mods that use minecrafts keybinding
this mod will not work for anything that directly uses hardware keybdinds

#
heres an example lua macros script that maps numpad buttons to f13-f22

lmc_device_set_name('MACROPAD', '<your device ID>')

lmc_set_handler('MACROPAD', function(button, direction)
    local vk = nil
    if     (button == 45)  then vk = 124 -- F13
    elseif (button == 35)  then vk = 125 -- F14
    elseif (button == 40)  then vk = 126 -- F15
    elseif (button == 34)  then vk = 127 -- F16
    elseif (button == 37)  then vk = 128 -- F17
    elseif (button == 39)  then vk = 129 -- F18
    elseif (button == 36)  then vk = 130 -- F19
    elseif (button == 38)  then vk = 131 -- F20
    elseif (button == 33)  then vk = 132 -- F21
    elseif (button == 107) then vk = 133 -- F22
    end

    if vk then
        if direction == 0 then
            lmc_send_input(vk, 0, 2) -- key up
        else
            lmc_send_input(vk, 0, 0) -- key down
        end
    end
end)