I was surfing the web for some information on champleve buttons (I only have one of these treasures). Anyway, I got sidetracked by this this cute article for sewing buttons (outside the holes) with embroidery floss.
My only champleve button...
Below is a small vintage MOP button (with beads and embroidery) added to the wedding collage this morning:
Vintage MOP button with carved chevron design