Outside mirror removal 2005 E500
 

I clipped a plastic construction barrel with my right mirror. The impact blew the glass out. I went to the dealer a bought a new mirror for $98. A tech was kind enough to install it for me. However, now my passenger mirror turn signal is out. The tech removed the mirror assembly easily with a screwdriver. There seems to be only one clip holding it in place. I am unable to remove the mirror.

Does anyone know the trick?