OK try this:

Again zero figure... Enter the  Fitting Room/New session.... Select your prop & figure, do nothing else just create a new figure. In the dialogues select nothing NO regroup No morphs....  Just an empty figure ..... Now back in the Pose Tab rename New Figure to Bellybutton ring(whatever) select that figure's abdomen...Menu/Object/ replace body part with prop/ Select the original bellybutton ring  and hit enter... test by conforming to figure and if satisfactory delete the new prop, save figure to library...

Y'all have a great day.