In a large mixing bowl cream butter and sugar. Add juices and peel, mix well (mixture may curdle from the citrus acid).
Add eggs and mix well.
Sift flour with baking powder and salt, add to creamed mixture and mix well.
Pour into two greased and floured 8" cake pans. Bake at 350°F for 20 - 25 minutes or until cakes tests done. Cool in pans for 10 minutes before removing to a wire rack to cool completely.
Frosting
Combine coconut, sugar, juices and 3 teaspoons of the orange peel. Let stand for 10 - 15 minutes or until sugar is dissolved.
Fold in whipped cream.
Spread between cake layers and over the top. Sprinkle with remaining orange peel.
Chill for at least 1 hour, store in the refrigerator.