I recently bought one cheap and I folded the crisper down. It was a pain because of the flaps which fit in the side grooves, but with a little gentle bending and wiggling I was able to get it down. It seems to work fine so far. Go SLOW and it should work out.
I would also like to have the CO2 tank outside, but I don't have a user manual and I'm worried about cutting through a line by drilling a hole. Anyone know where it's safe to drill a small hole (side or back)?