Add raisins to water; simmer until tender (3 to 5 minutes). Combine sugars, cornstarch and salt; stir into hot raisins. Cook slowly, stirring constantly, to full rolling boil; boil 1 minute. Remove from heat.
Blend in fruit peel and juices. Pour hot filling into pastry-lined 9" pie pan; dot top with butter. Adjust top crust; flute edges and cut vents.