Sift flour, sugar, baking powder and salt together in large bowl. Stir in dates, pineapple and milk. Pour into greased 13 x 9 x 2 inch baking pan. Combine water, brown sugar and margarine in saucepan. Bring to a boil and boil for 1 minute. Pour over pudding; do not mix. Bake in preheated 350-degree oven for 35 minutes or until done.