hi piorv2, just a thought, if you can't get satisfaction from the manufacturer and you're going to keep the set, try making or buying a rubber washer that can handle relatively high temps. when you tighten the screw, it should compress on the rubber washer, sealing out moisture.
if you can't find a suitable washer, but a high temp rubber pot holder and cut out a circle to fit the lid and handle properly.
The way that you wander is the way that you choose. The day that you tarry is the day that you lose.
Sunshine or thunder, a man will always wonder where the fair wind blows.