Clean the area the new tile will not.
Replace soap dish tile wall.
Install a replacement soap dish of either the retrofit style or in plain tile.
With a section of fine grit sandpaper in the 180 to 100 range roughen up the back of the soap dish and the ceramic tile wall.
Regrout after 24 hours.
Remove the broken soap dish a fractured soap dish may almost fall off the wall by itself.
Place masking tape over the tile.
Install a 1 4 inch masonry bit.
Use thin set and hold your new soap dish in place using long strips of duct tape crossing the new dish tile.
The tape will help keep the drill bit from slipping and ruining an adjacent tile when.
Shower soap dish holders do not last long.
To help it shatter drill.
Using a hammer and nail punch small divets into the tile in an x pattern.