Warm the ice cream at room temperature 15 minutes to soften. Gently pack and spread into the pie shell. (Don’t worry if the shell crumbles a bit, it will hold together once frozen.) Freeze solid. Combine the berries with the icing sugar, cutting the strawberries into halves or quarters first, if desired. Cut the pie into wedges and put on serving plates. Top with berries, garnish with mint and serve.