Reserve crepes. Combine cornstarch, sugar replacement, salt, milk, lemon juice and vanilla in saucepan. Cook and stir over medium heat until slightly thickened; remove from heat. Crush 1 cup (250 mL) of the blueberries and add to cream mixture. Return to heat, and cook and stir until thickened. Cool. Fold in remaining blueberries. Divide evenly between crepes, and fold or roll the crepes.