You can remove the rear seat, -it has bolts holding the bottom cushion) then punch out the appx 12x12 inch "ski hole", which is already cut, then tack welded back in - only to be removed again for the ski hole option (crazy germans...). Then you could easily probe in with a magnet. Tempting as it might be, I would resist the urge to send the kid in afer 'em. There are sharp edges and it might be hard to explain to the authorities.
Edit- Oh yeah, this requires access to the rear seat- DUH-