Scionlife.com - Bluetooth mic options for Pioneer stereo?

Hi, all.

So, I installed a Pioneer PT546-00140-BU radio in my Scion xD. So far, so good (and thanks to DannoXYZ for help.). What I'd like to do next is to ensure that I can use my mobile phone (an iPhone) through the radio, which means having a good microphone to be plugged into the head unit.

I have a couple of options for the microphone. One is the microphone which came with the car, which has a 3.5 mm plug. However, I do not see a 3.5 mm hole to plug into the back of the radio. I also purchased a microphone which is wired into a 28-pin male connector, but the 28-pin slot in the back of my radio is already spoken for. Instead, that connector is attached to the harness of the car, but there is also an eight-pin female connector which goes to the pins (according to a pinout map) which would take the microphone using five wires.

Is there an elegant solution to get one or the other of these microphones to work, or will I need to splice the wires of the second microphone into the wires of that empty eight-pin female connector?