Too Many Rear Pad Replacement Parts?

I am in the process of replacing the rear brake pads on my 2003 SWing. I have removed the old pads; however, the new pad set from Honda has more parts that what I removed. What I removed was only the pad (which is the metal plate pushed directly and in direct contact with the piston and the brake lining that is sintered onto this metal plate). What Honda sold me was the plate (with pad attached), a white material (thin) cut-out in the shape of a the pad, and a sheet metal backing plate designed to clip onto the metal brake pad plate. The piston would then push on the sheet metal that in turn pushes onto the thin white material, that pushed on the metal plate with pad attached, then pushes on the rotor. I am wondering why my rear pads (I am 2nd owner) don't have these extra parts and if I should install my rear pads with these extra parts? I have purchased front brake pads and they also come with these extra parts - plus it looks as if these extra parts are installed on my front wheel - but they definitely were not on my back. Hoping to put things back together today and get my bike back in the garage. Any suggestions would be appreciated. Thanks.

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Thanks BigBird for the clarification so that this installation may properly proceed!