Some dogs never do learn, unfortunately. A Great Dane mix that my family had never even learned to catch food. No matter how much she wanted it, or how close we got it to her mouth, it would bounce off her, land on the floor, and THEN she'd eat it! We finally gave up nefore someone accused of dog abuse for throwing food at our poor dog! This is not any indication of Dane intelligence - she was malnourished when we got her, and we always thought she suffered some brian damage as a result!
Better luck with your pup!