Cut the pork in half, rinse, and drain well. Place in a large bowl.
In a small bowl, combine rock salt, ¼ cup of brown sugar, and Prague salt. Stir until evenly distributed.
Rub the curing mixture over the pork, massaging it in to coat. Transfer the pork to an airtight container.
Cure pork for about 5 to 6 days, turning it over daily. Rinse and drain well.
Place on paper towels to remove excess liquid. Place the pork in a meat net and tie it tightly to shape the pork.
Place the pork in a large pot. Add pineapple juice and 2 ½ cups of brown sugar. Stir until the sugar is dissolved, then bring to a boil.
Lower the heat, cover, and cook for about 1 to 1 ½ hours or until the meat is tender. Remove the ham from the pot and, while still hot, use scissors to cut and remove the net.
Let cool, then rub in the remaining ½ cup brown sugar.
Arrange in a single layer on a baking pan and broil until caramelized.
Meanwhile, boil the pineapple-and-brown-sugar mixture until thickened.
Slice the ham into desired thickness and serve with the pineapple glaze.