Is this the ( bit hard rough feeling) very skinny ring thats under the pads and glued to the ring that keeps the pleather (upperside) and rubbery (underside) linked together..as otherwise i dont have any ring on my pads left.as .i first cut off the rubberflap right onto the ultimate corners of the pad itself...then i cut off the dustcover until u only keep a kind of hard ridge on the outside of the pads..its almost plastic feeling..but its glued to the pleather on top of it..!!! I tried to disconnect that from the pleather upperside..but its impossible to do that without destroying the pleather upperside! Even with a surgeon cutting knife!
You say you have glued the ring onto the pad? By default you should be able to just take it out.