7p6 Bluetooth loom (mic question)

Evening all. I’m in the process of fitting another RNS510 to the current car along with my old 7p6 Bluetooth kit. In the last car it was a pain to run the mic cable down the a pillar, under the carpet and into the Bluetooth box. I’ve seen a post on my-gti.com that suggests I can use the mic connector position in the quad lock connector, however the loom I have has a blank where it would connect to the mic. 

Is a loom available that will let me achieve what I want to do or will I have to bite the bullet and go under the carpet?