Sprinkle gelatin into 1⁄8 cup water in a small saucepan. Set aside for 5 minutes, then heat over low heat, stirring frequently, until gelatin is dissolved, about 1 minute. Cover to keep warm.
Place sugar in a large bowl. Make a well in the center and add corn syrup and glycerine without mixing. Pour the warm gelatin into the well and mix with a lightly greased rubber spatula or lightly greased wooden spoon until dough becomes too stiff to stir.
Spray hands with cooking spray or rub with a small amount of oil (dough will be sticky). Knead in bowl until all sugar is incorporated. Transfer dough to a lightly greased surface and continue kneading until smooth and satiny. Fondant should be the texture of clay (if it is too dry, add a few additional drops of water; if too sticky, add a bit more confectioners' sugar). Shape into a ball, flatten, and then wrap in plastic wrap. Set aside at room temperature for 20 minutes.
Meanwhile, place fruitcake on a lightly greased surface and brush with orange liqueur and cognac. On a lightly greased surface, roll out fondant into a round, about 1⁄4" thick.
Lift fondant onto fruitcake. (Small tears can be repaired by pressing between your fingers; fondant can also be rerolled at this point.) Mold fondant to cake with your hands, smoothing to avoid finger marks. Trim excess fondant from base. Working quickly (fondant hardens when exposed to air), form excess fondant into a ball and roll out about 1⁄4" thick. Using a sharp knife, cut 2 thick strips and place on cake and bend into the shape of a bow. From remaining fondant, cut holly leaves and roll out tiny berries.
Immediately transfer cake to a serving platter or storage tin. (Store, wrapped in plastic wrap, in refrigerator for up to 1 month.)