Here's a brief description by mikeg3 on how to replace your rear view mirror. It should be the same for your 190E -->
"I recently replaced the rear view mirror on my 83 300SD. If your mirror is like mine, it is held in place by 2 pinswith a spring between them. It looks something like this
<ZZZZZZZ>. To remove the mirror, pull on it moving it to the side. This should compress one of the pins & the mirror should come out.
To replace the new mirror, put one of the ends with the pins in place. Press on the other side and it should pop into place. I hope this is clear enough for you."
Hope this helps.
*Pearl Black AMG rims, yellow calipers
*Pearl Black grille and frame
*Euro headlights, clear blinkers
*Zebrano wood kit
*H&R springs/Bilstein shocks (yet to be installed)