Way to go daddie! Glad you are not going to give up. Sounds like Charlie is really loved and taken care of. Keep up with the exercises it will help out alot. If you recall there was a dog Tahoe with a broken neck or back that was paralyzed. The owners keep at it and he is getting a lot better. Here is a video of Tahoe on youtube. Prepare for tears, its really sad.
http://www.youtube.com/watch?v=vbirkF-ca04&NR=1