Since that is a Mach3 Controller LightBurn and MillMage are unlikely to ever directly control it. You can use the LinuxCNC profile currently to produce g-code for it but it will need some slight tweaks that you will need to figure out for your specific machine.
In 1.5 we will be releasing a “Custom G-Code” type that you will be able to specify what is included in blocks like “fire” and “tool on” to more easily support controls like this and need less post processing.