Trim fat from meat. Place meat in a resealable plastic bag set in a shallow dish. For marinade combine olive oil, white wine, vinegar, mustard, soy sauce, garlic, rosemary, black pepper, and cayenne. Pour over meat; seal bag. Marinate in the refrigerator for 2 to 4 hours, turning occasionally.
Drain meat, reserving marinade. For a charcoal grill, arrange medium-hot coals around a drip pan. Test for medium heat above the pan. Place meat on the grill rack over the drip pan. Cover and grill for 30 to 45 minutes or until done (160 degree F). (For a gas grill, preheat grill. Reduce heat to medium. Adjust for indirect cooking. Place meat on a rack in a roasting pan; place on grill rack and grill as above.)
Meanwhile, in a small saucepan bring the reserved marinade to boiling; reduce heat. Simmer, uncovered for 8 to 10 minutes or until reduced by about half. Strain mixture. Return strained mixture to saucepan. Stir in jam and lemon peel; heat through.
To serve, place sliced meat on a serving platter and spoon jam mixture over the meat. Garnish with fresh blackberries, if desired. Makes 4 servings.