Prepare and bake piecrust in a 9 inch pie plate. Cool completely on a wire rack.
Filling:
Combine mango nectar, sugar, lime juice, cornstarch, orange juice and eggs in a large saucepan, stirring with a whisk. Bring to a boil over medium heat, stirring constantly. Cook 1 minute, stirring constantly. Remove from heat. Stir in butter and rind. Spoon mango mixture into a bowl, place bowl in a large ice filled bowl for minutes or until it reaches room temperature, stirring occasionally. Remove bowl from ice and spoon mango mixture into prepared crust. Cover and chill 8 hours or until firm.
Meringue:
Place egg whites and salt in a large bowl and beat with a mixer at high speed until soft peaks form. Combine ½ cup sugar and water in a saucepan and bring to a boil. Cook, without stirring until candy thermometer registers 238 degrees. Pour hot sugar syrup in a thin stream over egg whites and beat at high speed until stiff peaks form. Spread meringue over filling. Garnish with rind if desired.