Place egg whiles in a large bowl; let stand at room temperature for 30 minutes.
Meanwhile, in another large bowl, cream butter and sugar until light and fluffy. Combine the coconut milk, milk and vanilla. Combine the flour, baking powder and salt; add to creamed mixture alternately with the milk mixture.
With clean beaters, beat egg whiles on medium speed until soft peaks form. Gradually fold into batter. Spread into a greased 13-in. x 9-in. baking pan.
Bake at 350 for 40-45 minutes or until cake springs back when lightly touched. Place pan on wire rack.
Poke holes in cake with a skewer, about 1/2-in. apart. Combine syrup ingredients; slowly pour over cake, allowing mixture to absorb into cake. Let stand for 30 minutes. Cover and refrigerate for 2 hours.
In a large bowl, beat cream until it begins to thicken. Add confectioners sugar and vanilla; beat until soft peaks form. Spread over cake; sprinkle with coconut.