Normally, your JVC Car Stereo will not allow direct connection to an Apple iPod.
However, there are several aftermarket interface adaptor that will allow you to do so:
1. Connect the iPod to a JVC KS-PD100 which in turn is connected to the CD changer jack of the KD-G720 (rear of the unit). Set the stereo to CD changer external input setting and you're ready to go;
2. Connect the iPod to an FM Transmitter such as the Griffin iTrip (w/ Dock connector) which in turn will broadcast the IPod music as an FM signal. Operating the KD-G720 on FM radio setting will receive the IPod's broadcast music.
Hope this be of some help to you. Pls post again how things turn up. Good luck and kind regards.