Place the raisins in the orange juice until they expand. Meanwhile, peel the bananas and slice them in half lengthwise. Heat the butter in a large frying pan and add the bananas, round side down. Cook the bananas for 2 to 3 minutes on each side turning them carefully with a spatula so as not to break them. Mix the sugar and nutmeg with the raisins and juice and pour it over the bananas. When ready to serve, remove the bananas from the frying pan, reserving the cooking juices, and arrange them on a hot plate. Heat the cooking juices to boiling, and add rum, and light it, pouring it over the bananas. The alcohol will burn off, leaving you with a rummy flavor on the sauteed bananas.