yeh you can, i bought a cable off ebay, it plugs straight in the back of standard HU. its sitting here if you want it mate. i bought an alpine HU 2 days later
You plug it into the back of the stereo where the 6cd changer connector would go, its easy to find, then when you scroll through 'source' (radio fm/mw/cd player etc) on your stereo you should have an 'Aux' option for that cable, if not you have to hold down 'expert menu' until a new menu pops up, then scroll through that menu, switch 'Aux' on then its good to go...
yeh you can, i bought a cable off ebay, it plugs straight in the back of standard HU. its sitting here if you want it mate. i bought an alpine HU 2 days later