Try a more modding-friendly way of adding commands.

Anims/cursortechup.txt

@@ -0,0 +1,2 @@
+hotspot topleft
+frame  cursortechup_0.png  5

LuaRules/Configs/ModCommands/tech_up.lua

@@ -0,0 +1,21 @@
+
+local data = {
+	name = "TECH_UP",
+	cmdID = 38412,
+
+	commandType = CMDTYPE.ICON_UNIT_OR_AREA,
+	isState = false, -- Hold fire etc
+	isInstant = false, -- Such as Stop, Self-D etc
+	humanName = "Tech Up",
+	actionName = "techup",
+	cursor = "Techup",
+	image = "LuaUI/Images/commands/Bold/tech_up.png", -- If a state, then this should be a list of images.
+
+	onCommandMenuByDefault = true,
+	position = {pos = 7, priority = 0.1},
+	stateNames = nil, -- A list of what the states are called.
+	stateTooltip = nil, -- A list of tooltips to use for each state.
+	tooltip = "Tech Up: Upgrade the constructor's factory to the next tech level, or any other structure to the current tech level.",
+}
+
+return data

LuaRules/Configs/customcmds.lua

@@ -7,7 +7,7 @@
      obvious where the extra commands are coming from). ]]
 
 -- if you add a command, please order it by ID!
-return {
+local commands = {
 	RETREAT_ZONE = 10001,
 	RESETFIRE = 10003,
 	RESETMOVE = 10004,
@@ -112,3 +112,11 @@ return {
 	--[[ WARNING!! Only BASE VANILLA ZK commands belong here!
 	     See the bigass chunk of text at the top of the file. ]]
 }
+
+local commandFiles = VFS.DirList('LuaRules/Configs/ModCommands')
+for i = 1, #commandFiles do
+	local fileData = VFS.Include(commandFiles[i])
+	commands[fileData.name] = fileData.cmdID
+end
+
+return commands

LuaRules/Configs/modCommandsDefs.lua

@@ -0,0 +1,20 @@
+
+local commands = {}
+local commandsMap = {}
+local commandFiles = VFS.DirList('LuaRules/Configs/ModCommands')
+for i = 1, #commandFiles do
+	local fileData = VFS.Include(commandFiles[i])
+	fileData.cmdDesc = {
+		id      = fileData.cmdID,
+		type    = fileData.commandType,
+		tooltip = fileData.name, -- Overridden by luaUI
+		name    = fileData.humanName,
+		cursor  = fileData.cursor,
+		action  = fileData.actionName,
+		params  = {},
+	}
+	commands[#commands + 1] = fileData
+	commandsMap[fileData.cmdID] = fileData
+end
+
+return commands, commandsMap

LuaRules/Gadgets/unit_tech_k.lua

@@ -14,6 +14,17 @@ function gadget:GetInfo()
 	}
 end
 
+if not ((modoption == "1") or (modoption == 1)) then
+	return
+end
+
+--------------------------------------------------------------------------------
+--------------------------------------------------------------------------------
+
+local CMD_TECH_UP = Spring.Utilities.CMD.TECH_UP
+local modCommands, modCmdMap = VFS.Include("LuaRules/Configs/modCommandsDefs.lua")
+local techCommandData = modCmdMap[CMD_TECH_UP]
+
 --------------------------------------------------------------------------------
 --------------------------------------------------------------------------------
 
@@ -23,6 +34,9 @@ local deathCloneDefID = {}
 local Vector = Spring.Utilities.Vector
 
 if not gadgetHandler:IsSyncedCode() then
+	function gadget:Initialize()
+		Spring.AssignMouseCursor(techCommandData.cursor, "cursortechup", true, true)
+	end
 	return
 end
 
@@ -129,6 +143,7 @@ local tech = 1
 function gadget:UnitCreated(unitID, unitDefID)
 	SetUnitTechLevel(unitID, tech)
 	tech = tech%10 + 1
+	Spring.InsertUnitCmdDesc(unitID, techCommandData.cmdDesc)
 end
 
 function gadget:UnitDestroyed(unitID, unitDefID, teamID)

LuaUI/Configs/border_menu_commands.lua

@@ -275,7 +275,7 @@ local overrides = {
 	[CMD_UNIT_FLOAT_STATE] = { texture = {imageDir .. 'states/amph_sink.png', imageDir .. 'states/amph_attack.png', imageDir .. 'states/amph_float.png'}, caption=''},
 	[CMD_SELECTION_RANK] = { texture = {imageDir .. 'states/selection_rank_0.png', imageDir .. 'states/selection_rank_1.png', imageDir .. 'states/selection_rank_2.png', imageDir .. 'states/selection_rank_3.png'}, text=''},
 	[CMD_FORMATION_RANK] = { texture = {imageDir .. 'states/formation_rank_0.png', imageDir .. 'states/formation_rank_1.png', imageDir .. 'states/formation_rank_2.png', imageDir .. 'states/formation_rank_3.png'}, text=''},
-	}
+}
 
 -- noone really knows what this table does but it's needed for epic menu to get the hotkey
 local custom_cmd_actions = {	-- states are 2, not states are 1
@@ -367,5 +367,11 @@ local custom_cmd_actions = {	-- states are 2, not states are 1
 	formation_rank = 2,
 }
 
+local modCommands = VFS.Include("LuaRules/Configs/modCommandsDefs.lua")
+for i = 1, #modCommands do
+	local cmd = modCommands[i]
+	custom_cmd_actions[cmd.actionName] = cmd.isState and 2 or 1
+	overrides[cmd.cmdID] = {caption = '', tooltip = cmd.tooltip, texture = cmd.image}
+end
 
 return common_commands, states_commands, land_commands, sea_commands, advland_commands, advsea_commands, special_commands, globalCommands, overrides, custom_cmd_actions

LuaUI/Configs/customCmdTypes.lua

@@ -248,4 +248,21 @@ for name, data in pairs(custom_cmd_actions) do
 	fullCustomCmdActions[name] = data
 end
 
+--------------------------------------------------------------------------------
+--------------------------------------------------------------------------------
+
+local modCommands = VFS.Include("LuaRules/Configs/modCommandsDefs.lua")
+for i = 1, #modCommands do
+	local cmd = modCommands[i]
+	custom_cmd_actions[cmd.cmdID] = {
+		cmdType = (cmd.isState and 2) or (cmd.isInstant and 3) or 1,
+		cmdID = cmd.cmdID,
+		name = cmd.humanName,
+		states = cmd.stateNames,
+	}
+end
+
+--------------------------------------------------------------------------------
+--------------------------------------------------------------------------------
+
 return fullCustomCmdActions

LuaUI/Configs/integral_menu_commands.lua

@@ -352,6 +352,15 @@ local special_commands = {
 --------------------------------------------------------------------------------
 --------------------------------------------------------------------------------
 
+local modCommands = VFS.Include("LuaRules/Configs/modCommandsDefs.lua")
+for i = 1, #modCommands do
+	local cmd = modCommands[i]
+	cmdPosDef[cmd.cmdID] = cmd.position
+end
+
+--------------------------------------------------------------------------------
+--------------------------------------------------------------------------------
+
 return cmdPosDef, factoryUnitPosDef, factory_commands, econ_commands, defense_commands, special_commands
 
 --------------------------------------------------------------------------------

LuaUI/Configs/integral_menu_config.lua

@@ -638,6 +638,15 @@ end
 --------------------------------------------------------------------------------
 --------------------------------------------------------------------------------
 
+local modCommands = VFS.Include("LuaRules/Configs/modCommandsDefs.lua")
+for i = 1, #modCommands do
+	local cmd = modCommands[i]
+	commandDisplayConfig[cmd.cmdID] = {tooltip = cmd.tooltip, texture = cmd.image, stateTooltip = cmd.stateTooltip}
+end
+
+--------------------------------------------------------------------------------
+--------------------------------------------------------------------------------
+
 return commandPanels, commandPanelMap, commandDisplayConfig, widgetSpaceHidden, textConfig, buttonLayoutConfig, instantCommands, cmdPosDef
 
 --------------------------------------------------------------------------------

LuaUI/Configs/integral_menu_culling.lua

@@ -115,4 +115,17 @@ local defaultValues = {
 	--[CMD_FIRE_TOWARDS_ENEMY] = true,
 }
 
+
+local modCommands = VFS.Include("LuaRules/Configs/modCommandsDefs.lua")
+for i = 1, #modCommands do
+	local cmd = modCommands[i]
+	configList[#configList + 1] = {
+		cmdID = cmd.cmdID,
+		default = cmd.onCommandMenuByDefault,
+		name = cmd.humanName,
+		state = cmd.isState
+	}
+	defaultValues[cmd.cmdID] = not cmd.onCommandMenuByDefault
+end
+
 return configList, defaultValues