Mission equipment is BA cargo. As such, treat it like you would cargo on another unit. This means in particular that, while you can put almost anything in there, it has no effect in game terms, as it's being carried in boxes or slings or what have you and then sealed in a compartment. It doesn't allow you to create essentially an omnimount to put whatever you need in there. Anything with a game effect inside is stored in such a way as to be unusable at the tabletop.