AUX in MFD2 Navi HELP!!

[kierhanlon6]

hello i have brought a aux port that fits in the blanking plates near the gear knob. i brought it from double apex. i brought it with the mfd2 wiring harness so its just plug and play. i push the cd button on the head unit and bellow cd6 button there is a aux button push that and nothing. i have a 6 disc changer under my arm rest in the centre console.any help please?
cheers