Has anyone located the headphone button contact point?

I’m a bit of an amateur here, so I’m hoping for a bit of help.
I’m trying to find the contact point for the headphone button on my V2 in order to attach an external button to it. The internet hasn’t been terribly helpful, and it seems like the trace goes under the right thumbstick, which makes it more challenging to follow.
Has anyone here mapped out where it goes to?
See photos for mobo shots.