Combine splenda, flour and salt in heavy pot. Stir in milk. Stir over medium heat until thick and comes to a boil. Remove from heat, add beaten egg yolks. Cook 2 mins. Remove from heat again, add vanilla, butter, and flaked coconut. Mix well and pour into graham cracker pie crust. Cover with meringue. Bake at 375 degree oven until browned. About 5-8 mins.
To make meringue: Beat egg white on high. Slowly add Splenda while beating until it stiffens. About 1-2 teaspoons.