In small bowl, mix soy sauce, oil, brown sugar, lime juice, sherry, ginger, and garlic until sugar is dissolved. Reserve 1/4 cup marinade for basting.
Place beef in large resealable plastic bag and add remaining marinade. Seal bag, turn to coat. Marinate in refrigerator 12-24 hours.
Remove beef from marinade, discard marinade.
Preheat grill to medium high.
Cook 5 to 7 minutes. Turn once and baste with reserved 1/4 cup marinade. Cook until internal temperature reaches 145°F. Remove from heat, let stand 5 minutes. Slice steak diagonally across grain into thin slices.