Trim fat, butterfly roast by cutting lengthwise to ½ inch of other side.
Place in dish or large zip-loc.
Combine soy sauce, ginger, and garlic, pour over roast.
Refrigerate 3 hours or more.
Turning occasionally.
Remove roast, discard marinade.
Combine brown sugar, honey and sesame oil in a saucepan.
Cook over low heat until sugar dissolves.
Coat grill rack with cooking spray.
Place roast over medium hot coals (350-400°F).
Brush with mixture.
Cook 20-25 minutes or until meat thermometer reaches 160°F.
Baste frequently.