Stir together margarine, brown sugar, and water.  Pour onto bottom of 9" round cake pan.  Arrange pineapple and cherries in the pan; set aside.  In a medium mixing bowl, stir together flour, sugar, and baking powder.  Add rice milk, 1/4 cup margarine, egg replacer, and vanilla.  Beat on low speed until combined; beat on medium speed for 1 minute.  Spoon batter over fruit in the prepared pan.  Bake at 350 for 30-35 minutes or until toothpick comes out clean.  Cool on wire rack for 10 minutes.  Loosen cake from pan and invert onto a plate.  Serve warm.