Sauté first 4 ingredients in 2 tablespoons hot oil in a large skillet over medium-high heat until tender. Remove from pan, and keep warm.
Cook scallops in remaining 1 tablespoon oil in skillet over medium heat 5 to 6 minutes; turn scallops over, and cook 3 to 5 minutes or until golden brown. Remove scallops from pan, and keep warm.
Add 2 tablespoons soy sauce, orange rind, and next 3 ingredients to skillet. Bring mixture to a boil, and cook over high heat about 2 minutes. Gradually whisk in butter and remaining 1 tablespoon soy sauce until well blended. Serve immediately over vegetable mixture and scallops. Garnish, if desired.