1.Preheat oven to 160*C (140*C fan forced).
2.Carefully remove the rind from the ham, leaving a good layer of fat intact. Leave rind around the shank of the leg. Score the fat in a diamond pattern, being careful not to cut all the way through to the meat of the fat will dislodge during cooking. Make a few deep incisions into the meat with a small sharp knife.
3.Combine the pineapple juice, brown sugar, jam, mustard and salt in a large saucepan. Bring to the boil, and stir, boiling for around 15 minutes or until reduced to about 1 1/3 cups. The mixture will thicken as it cools and should have the consistency of a thick syrup. Be vigilant, as the mixture can bubble up to the brim of the pot. Allow to cool.
4.Baste the ham generously with the glaze, making sure that some gets into the deep incisions. Place the ham in a large baking dish and bake for 3 hours, basting with the marinade several times.