Soften gelatin in cold water in a medium mixing bowl; add boiling water; stir until gelatin dissolves. Add sugar, and stir until sugar dissolves. Let cool 15 minutes. Stir in lemon rind and juice. Chill until consistency of unbeaten egg whites.
Beat egg whites (at room temperature) until soft peaks form. Gently fold into lemon mixture. Spoon into a 1-quart serving dish, and refrigerate until firm.
Garnish pudding with strawberries. Spoon pudding into individual serving bowls, and serve with chilled Custard Sauce.