I am assuming you have done all the research into the physiological issues that are causing an older child or teenager to still bedwet? My daughter is ADHD and although she did not wet the bed, she had these daytime accidents that made absolutely no sense. It wasn't behavioral and I couldn't pin down why she did it in the day and not night. After many doctor's visits to her ped, we were referred to a pediatric urologist who diagnosed her in five minutes worth of questions and no physical exam. Had to do with how the brain received the signals from her body that she had to go. This doctor saw this problem in many of her ADHD patients and put her on a medication that immediately worked. She said the problems usually corrects itself by adolescence when her brain and body are finally on the same wave length and she was right.
I know this isn't your original question, but since you didn't put any history, I thought I'd put that out there because as a mother, before I just accepted that this was the way it is, I would want to be sure I explored every avenue of trying to correct the problem instead of just putting a band aid on it.