Combine fructose, the 1 1/2 cup (375 mL) water, and salt in a medium-size, heavy saucepan.
Heat to boiling.
Combine cornstarch and the 1/4 cup (60 mL) cold water, stirring to blend thoroughly.
Add to boiling mixture, stirring constantly.
Cook and stir until mixture is clear and thickened.
Remove from heat.
Beat egg yolks and lemonjuice together.
Slowly stir into hot mixture.
Return to heat and cook until mixture begins to boil.
Stir in margarine and lemon peel.
Cover and cool to room temperature.
Beat egg whites and salt together until soft peaks form.
Gradually add sugar replacement.
Beat just until peaks are stiff.
Pour lemon mixture into pie shell.
Top with egg whites, sealing edges.
Bake at 350°F (175°C) until peaks begin to brown.