Hello, Have you tried sweat soldering your joint? As mentioned, the gold and silver will want to mix at the point of soldering. By 'smearing' the melting silver solder onto the base of your bezel, then placing it on the silver and fluxing the joint, I think you will have the least chance of that gold-silver mix. Of course that means you pull the heat away immediately when you see flow.
However, sweat soldering with gold solder would be even easier - particularly if you use the x-easy solder.
Let us know how your piece finished out.
Judy in Kansas, who is trying to gin up the energy to prepare for the last show of the year!!