you may have to regroup and rig, unless the lid is a different material.

if the lid  is a different material you can make a pose file to 'hide'it ( afaik)

or manually hide it in material room.

failing that, the lid and box must be grouped as separate 'parts' ( this is how Modo groups things) and the box/lid bones must be named to match the groups.

then you can delete the 'lid bone' in scene