Hrrm, I'm not sure. I took a look at mine and can't work out if the plastic net-surround is glued/clipped/screwed onto the back of the seat.
The oemparts site isn't of much use either:
RETROFIT, NET BAG AT SEAT BACKREST
Strangely enough, that's the first part i've seen that has a big "SKILLED PERSONNEL
ONLY" instructions - maybe it is actually quite tricky...