Place ham, flat side down, on rack in roasting pan; pour in 1 cup water. Cover pan tightly with foil; roast in 325ºF (160°C) oven, about 2-1/2 hours.
Meanwhile, in small saucepan, bring apple juice, 1/2 cup water, mustard, sugar,cinnamon, nutmeg and vinegar to boil; boil until reduced to 3/4 cup, about 7 minutes. Brush half over ham.
Bake, covered and brushing with remaining glaze halfway through, about 1 hour. Transfer to cutting board and tent with foil; let stand for 20 minutes before carving.