Outside Mirror Glass, '88 5KSQ

["Christopher Ritchie" <cjr1@gte.net>]

I am trying to replace the glass in my RH door rear view mirror.  I am
replacing the '88 flat glass with the convex '89 glass.  I am trying first
to get the '89 glass out of the assembly.  I have the complete '89 rear view
mirror assembly.  The Bentley, at 66.6, states that it is removed by:

inserting a screwdriver up in the slot in the bottom of the housing;
engaging the center notches on the clamping ring; and,
turning the clamping ring counterclockwise.

I have been fiddling with this all day, and am quite po'd.  I don't see any
d**n notches or clamping ring in there.  What am I missing?