Preheat oven to 350. Grease and flour three 9 X 4 cm round pans. Sift flour with baking powder and half t salt. In large bowl of mixer, at high speed, beat butter and 2 c sugar until light. Add 4 eggs, one at a time; beat after each addition.
Continue beating, occasionally scraping bowl with rubber spatula, until fluffy, about 2 minutes. At low speed, beat in flour mixture ( in fourths) alternately with milk (in thirds), beginning and ending with flour. Add vanilla. Beat just until smooth, about 1 minute.
Pour into pans. Baske 25-30 minutes, or until surface springs back when gently pressed with fingertip. Cool in pans on wire racks for 10 minutes. Remove from pans; cool on racks.
Filling: In small saucepan, mix 1 cup sugar with cornstarch and salt. Gradually stir in juices and the water. Bring to boiling over medium heat, stirring. Remove from heat. Add yolks one at a time, beating well after each addition. Bring to boiling, stirring; boil 1 minute. Remove pan from heat. Stir in peels and a few drop of color. Turn=7F into bowl; cool over ice water.
Make frosting: In medium bowl, combine cream and confectioners sugar. Refrigerate half hour. Beat until stiff. Measure 1 cup whipped cream and with a whisk, fold into filling.
Place one cake layer, top side down, on large cake platre. Spread with half of filling almost to outer edge. Repeat with second layer and rest of filling, place top layer, right side up. Frost with rest of whipped cream; decorate with coconut and lime. Refrigerate.