CD-player Y-cable - still available?

Several references say that installing a pre-2003 Toyota (single) CD player into a Gen 1 Prius requires an adapter Y-cable, part no. 08695-00370. For my early 2003 Prius, I ordered this cable online by this part number and got a Y-cable where the two Y cable ends have plugs that are too small to fit the radio and its cable. The base of the Y-cable has a larger plug that fits the CD player cable correctly. Is this part number (or cable) no longer accurate, or did I get the wrong cable for the right part number? Does anyone have a source for the right cable? The local Toyota dealer says that the cable part number fits a Celica and says that he does not have a part number for the Prius Y-cable, and he cannot order the older setting kit that included the Y-cable (also reported by others). I could sure use some help!