Mitsubishi Pajero how to deactivate diff lock-up temporarily

I don't do serious offroading but many times while pulling our heavy caravan I would like to use Low Range. But starting on steep pinches, pulling out of streams, creeping on narrow tracks, even on hard sand, the trans wants to "wind-up". This model only has 2H,4H, 4Low(locked), 2Low(locked). Is there a way to modify it to switch out the difflock when required. John