Prepare gas or charcoal grill to medium-hot (375-425 degrees F.) for indirect cooking. Place drop pan in center, not over heat source (for gas grill, turn off center burner; for charcoal grill, bank coals on either side). Score top and sides of ham with a knife in a crisscross pattern; mix all remaining ingredients except the glaze ingredients and rub into surface of ham. Place ham, score side up, in center of grill over drop pan. Cover and grill for 1 - 1 1/2 hours (adding 6-8 briquettes to charcoal grill if necessary to maintain heat), until internal temperature of ham (measured with a meat thermometer) reads 140 degrees F. (about 15-18 minutes per pound.) Combine marmalade and orange juice in a small bowl; brush over ham and grill 5 minutes more. Remove ham from grill and let stand 15 minutes.