Combine herb butter ingredients in a small bowl and set aside.
In a bowl, combine oil, soy sauce, lemon juice, lemon zest and garlic. Blend.
Place steaks in a single layer in a shallow baking dish. Pour marinade over them, reserving 1/3 cup. Marinate in refrigerator about 45 minutes, turning occasionally.
Drain fish. Discard used marinade. Place steaks in well-greased hinged grill. Cook about 4 inches from heat until done on one side, about 6 to 8 minutes. Baste with reserved marinade and turn. Cook on other side until done, about 6 to 8 minutes. Spread with herb butter.