JVC DIY line in cable (KS-U57/KS-U58) help :)

hey guys,
i have a cheap JVC head unit on one of my family's cars, it's KD-G631

thing is, on friday im leaving on vacation and i'd really wanna have an input jack attached to it.
unfortunately jvc does not import it's original parts to Greece, and the one i've ordered from ebay wont be here before im gone. so im trying to make a diy cable to connect my iphone to the headunit.

ive looked around for a schematic/pinout with no luck, so here's a drawing of the plug, maybe some1 has the knowledge to help me out