[Captain von Keldunk]

Hello
Hint 3, It is legal to buy in Willemstad but contrabant at destination.
I do not think that these store contraband items will change over time.
See here:
Islands[n].Trade.Export.id5 = GOOD_POWDER;
Islands[n].Trade.Export.id6 = GOOD_SUGAR;
Islands[n].Trade.Export.id7 = GOOD_PAPRIKA;

Islands[n].Trade.Import.id1 = GOOD_CINNAMON;
Islands[n].Trade.Import.id2 = GOOD_FOOD;
Islands[n].Trade.Import.id3 = GOOD_BRICK;
Islands[n].Trade.Import.id4 = GOOD_FRUITS;
Islands[n].Trade.Import.id5 = GOOD_PLANKS;
Islands[n].Trade.Import.id6 = GOOD_COPRA;
Islands[n].Trade.Import.id7 = GOOD_ALE;

Islands[n].Trade.Contraband.id1 = GOOD_SLAVES;
Islands[n].Trade.Contraband.id2 = GOOD_LINEN;
Islands[n].Trade.Contraband.id3 = GOOD_CHOCOLATE;