Not that I am an expert on this subject but I wet the bed when I was younger and didn't stop until I was a teenager. I was never great at school but somehow managed to scoot by unnoticed. After high school graduation I went to a community college until my grades were good enough for exceptance into a large university- which I graduated from and went on to have a fufilling career and a wonderful family. The reason I'm writing this is because things do turn around. Drawing too much attention to the bedwetting can actually make it worse in my oppinion. I think there is an emotional aspect to it that your daughter doesn't have control over. My parents took me to every expert across the state and never came up with a solution. If you read about enuresis one of the things you will find is hiding clothes and sheets is all part of it- not sure why- I think for me it was shame and embarassment. Good luck! If you have not found a medical reason for the bed wetting I bet your daughter will outgrow it soon.
It would be prudent to arrange an evaluation for her with a mental health clincian. You might also consider some testing, such as a neuropsychological evaluation. While she is undoubtedly intelligent, there may be some learning obstacle that accounts for her uneven school performance. What treatments have been attempted to address the nocturnal enuresis?