I wish I could give you an answer but I don't think there is one!
The side effects are horrible and it's all a case of pro's and con's I guess.
Pred really does work wonders on Crohn's symptoms, It's just unfortunate that it causes so many problems of its own, The only way I ever used to get around the insomnia was by going to the gym doing a ridiculous run or something which occasionally made me tired enough to sleep!.. otherwise, i'd just give up trying to sleep because it only made it harder so i just used the hours of the night to read a book or something. Thats how I read all the harry potter books.. lol