Casein protein is supposed to be digested over a 6-8 hour period. This is due to the various changes the protein goes through (it converts to a gel within the body, and is then absorbed by the intestines.) I would use a mixture of casein and whey before bed, this would give you approximately 8 hours of protection against catabolism.
However, If fatburning where my goal the only thing I may take before bed is glutamine. It has no calories, and has anecdotal studies supporting it's gh releasing properties, and it is anticatabolic.. However, I would not consume calories at least an hour or 2 prior to going to sleep.