Hilux dual cab rear speaker connections

Hi,

Can anyone with an SR5 or Hilux dual cab with rear speakers connected tell me where / what the plug configuration is under the front internal panels? To clarify, if you remove the two tringular shaped panels where the front drivers / passengers feet would normally sit their are 3 or 4 plugs. The front speakers are connected to one of them, if anyone with has pulled these off to fit accesories etc and can advise me where to plug in the rear speakers I would greatly appreciate.
My vehicle is a 2003 hilux dual cab 3.0TD. I have already installed the speakers and ran the cable but was stumped when looking at these plugs. Have asked the techs at JB Hi-FI and Strathfield but they have no idea and say that they won't connect rear speakers to a toyota factory head unit? Any help would be much appreciated.