For sauce, in a small saucepan heat juice concentrate, mustard, rosemary, and garlic over medium heat about 5 minutes or until slightly thickened, stirring once.
Arrange preheated coals around a drip pan in a covered grill. Test for medium heat above pan. Place pork on grill over drip pan. Brush with sauce. Cover and grill for 30 to 45 minutes or until juices run clear (160 degrees F. to 170 degrees F.), brushing again with sauce during the last 10 minutes of grilling. Remove pork from grill and cover with foil. Let stand for 15 minutes before slicing. Garnish with fresh rosemary, if desired. Makes 6 servings.