That does not show the 4 extra screws located on the upper side of the grill.
I got the 2 screws which you simply have to pinch to get them through. However, there are 2 other screws which are screwed into a sleeve which "explodes" at the tip so that it can not be pulled out. Argh, pulling won't get it out. The plastic is more likely to break.
Any suggestions?