Combine raisins and water in saucepan.
Bring to a boil, reduce heat and simmer 5 minutes.
Remove from heat; allow to cool slightly.
Drain.
Combine flour, baking soda and salt in sifter, and sift twice.
Return flour mixture to sifter.
Cream together shortening and sugar replacement in medium mixing bowl.
Add egg and beat well.
Add sifted flour mixture alternately with buttermilk, beating well after each addition.
Stir in drained raisins.
Pour mixture into a well greased and floured 9 in. (23 cm) square pan.
Bake at 350°F (175°C) for 30 to 40 minutes, or until done.
Cut into 9 squares.
Cut horizontally through center of each square and fill evenly with softened ice milk.
Freeze until firm.