I'm willing to bet it is a software setting. With any luck, in a few years someone will come up with an aftermarket tool to access and change settings. For example, in the BMW world, USA cars don't get to roll their windows up, from the key fob, close the auto hatch from the key fob or inside button, etc. etc.
All these parameters can be 'coded' to work to your preference, they are just set that way to to US regulations/lawyers/etc. The BMW world has multiple tools, and/or services that will allow you to do this, or do this for you.
One can hope the same will eventually be available for Grenadier owners.
Until then, Its probably going to require some type of creative work around. Have to get out the multimeter and start taking panels apart and probing. I'd say the first place I'd start is to see if the switch itself is dead until the other parameters are met. If you are lucky, and it just doesn't get power until these parameters are met, you may be able to feed it an optional power source that is live when the ignition is on, or when the parking lamps are on, or whenever you want them to work..
Worst case scenario, as
@parb mentioned, pull the connector from the switch, run your own circuit and use the switch to activate it (don't forget the relays!)