Place strawberries in large bowl; let stand at room temperature for about an hour or until thawed. Add sugar and liqueur; toss to mix. Let stand 15 minutes to marinate.
Meanwhile, line 9x5-inch loaf pan with plastic wrap. Arrange ladyfingers vertically around inside of pan, fitting tightly.
Drain 1/2 cup strawberry liquid from marinated strawberries; set aside. In food processor bowl with metal blade, puree strawberries and remaining liquid; pour into large bowl.
In small bowl, combine reserved 1/2 cup strawberry liquid, the orange juice and gelatin; mix well. Let stand 5 minutes to soften gelatin. Pour mixture into small saucepan. Heat over low heat, stirring constantly, until gelatin is dissolved. Stir gelatin mixture into pureed strawberries.
In medium bowl, beat 1 cup of the whipping cream and 1 tablespoon of the powdered sugar at high speed until stiff peaks form. With wire whisk, fold whipped cream into pureed strawberry mixture. Mixture should begin to thicken slightly. If not, place bowl over larger bowl of ice and gently stir with whisk until mixture begins to thicken slightly. Spoon into ladyfinger-lined pan. Refrigerate 4 hours or overnight before serving.
To serve, beat remaining 1/2 cup whipping cream with remaining 1 tablespoon powdered sugar until stiff peaks form. Unmold loaf onto serving platter. Cut into slices; place on individual dessert plates. Garnish with whipped cream. Store in refrigerator.