Oh how I love this piece.  It's great when I'm feeling gothy, or agressive, or on Halloween :)

You can use a frame like I did, or mount it in a bezel, or drill and add a jump ring, or add a pin to the back.

You'll need to pour in layers to get this dimension.

Step 1: Pour clear resin deep enough to cover your charm, and a bit more.  Allow to thicken for 1 hour, then insert metal charm, do not push it all the way down or it can come through the resin on the front, and won't look as nice.  Allow to set for at least 12 hours, then demold

Step 2:  Prop your cast cabochon in a smaller cavity and make sure the top is level. Cut a circle out of the Resin Color Film and the Texture Film a bit smaller than the flat part of your casting.  Apply a thin layer of resin, then push your Resin Color Film down, use your mixing wand to push down across the surface, to eliminate any air pockets.  Apply another thin layer of resin and repeat with your Texture Film Circle.  Allow to set for at least 3 hours, then...

Step 3: Mix Black Resin Colorant into your resin, use this to dome up your piece.  Allow to thicken for 1-1/2-2 hours, then use this thickening black resin as a glue for the bezel/frame, and whatever finding you plan to use for a bail - can be a flat-back bail or a headpin wrapped with a bead around the bezel/frame.

Allow to set up at least 12 hours before handling to prevent fingerprinting.