Has anyone worked out how to do this yet, I sure there wil be a simple knack to it.

 

i did a 96 xj6[they should be the same type unit].i found a good mirror in an engine fire car,the plastic housing was damaged.i had nothing to loose so i pryed the case where the seem is and it came apart.use a sharp putty knife an start at the top or bottom,not the sides cause theres no give.work it back and forth gently till you hear it unsnap,then proceed around the circumfrence...steve.