If you look carefully at the screen you will notice a 'post' that fits into
a recess in the lower section of the window.  Drilling a small hole very
carefully in the vicinity of this post so that a small sheetmetal screw can
be used to secure the lower corner of the screen has worked for me.  The
plastics are very brittle with age, as many of us are and do not respond
well to aggravation by sharp objects.  Pix to be posted to the vanagon yahoo
site if you like.

P