You haven't really explained this well enough for me understand what exactly you are doing. So perhaps you should start with defining exactly what you want to do here.
I would think that you would have to define some sort of predictable pattern to some part of it before you could build a regex to capture the part you want. And if you don't alter the case in any way when you break the string apart, you shouldn't have to worry about the case for the piece you grab.