Cell hands free mute connection ford expl

I have a 2004 Ford Explorer with the simple AM/FM radio and single CD. Am installing a handsfree cell hookup and it has a mute wire that has to be connected to the back of the radio. Question, as this model doesn't have a cell mute botton on the face, does it mean that this wire hookup won't work in the rear of the unit? Or is the a connection possible. Where do I connect it if affirmative. Thanks,

Steve

Pull the stereo out & turn it on ( just the stereo, not the full ignition) probe the holes at the back with a test lamp till the stereo mutes if it dont, then~

if the mute wire pulls low to ground, connect it to pin 85 of a starndard SPDT or 5 pin relay, 86 can be put to a perm12v.

Cut the ignition wire to the back of the stereo leaving plenty of wire either side & connect the wire from the stereo side to pin 30 & the car side to 87a, insulate pin 87 with a fully insulated female spade connector.

When the phone is in use, the mute wire pulls low to ground, because of the 12v feed to the other side of the coil, the relay will energize throwing the switch across the the terminals 30 & 87 This will then turn the ignition feed to the stereo off when the phone rings!