Preheat oven to 325 degrees. Line 24-count muffin tins with paper liners. In a blender, combine cream cheese, 1 cup Splenda, eggs, 1 1/2 tsp vanilla, and lime juice.  Blend until creamy. Pour batter into muffin liners, filling cups approximately 2/3 full. Bake 40 minutes. Remove cupcakes from oven.  They should fall in the middle, forming a basin for the filling.

Mix sour cream, 1/4 cup Splenda, 1/4 tsp vanilla extract, and caramel sauce. Spoon filling into basin in the middle of each cupcake.  Return to oven and bake for 5 minutes.

Remove from oven and allow to cool for 30 minutes, then refrigerate for 2 to 4 hours before serving. Each cupcake has 2.7 grams of carbohydrates.