So from the date of the most recent post, this seems to be an issue that never was resolved and I'm stumbling upon a bit late in the thread but...
I was sitting here using my MC721*/A or MacBookPro8,2 and had started using a 3rd party online client to team-speak/voice-chat for a game. Previously I had only used integrated/in-game software based voice-chat interfaces so this was the first time I actually encountered this issue.
And I find it bizarre. Read through all the possible solutions and methods of trying to utilize a headphone/mic combo input (such as the one provided with iPhones and other apple devices). Now that I am addressing the issue from a Win 7 64x level approach, I'm completely baffled that it isn't possible/isn't a solved/addressed issue with the Apple hardware and bootcamp drivers.
This is even stranger to me because previous while playing (SoE's Everquest 2) and using the in-game voice interface, the options allowed me to select my headphone input as both the incoming sound device and as an independent playback device. This was nice because you could select whatever permutation of the options was best fit and even had some level of scrubbing/masking of speaker playback that might come through on the input mic. I would sometimes use the built-in mic just because I thought I sounded more clear from a distance than 2 inches from my mouth, but when the fans where going at full-steam I would switch to the headphone based mic and had no issue whatsoever selecting it and using it as the input device.
1 - I had the earbuds plugged into the audio-out/headphone symbol jack
2 - I have now attempted to plug in via every method I was able.
a) have tried having 1 set up earbuds in 1 jack for volume (audio out works for that at least 😉) and a second pair in the audio in/optical digital audio in port - Resulted in good audio out but no recognized audio input via jack.
b) Bose provided a airline headphone adapter that plugged into both inputs perfectly and attempted using single earbud via adapter just for the heck of it and only audio out was recognized
c) Restarting with input devices plugged... (we can go on and on here) but needless to say I was ultimately unsuccessful.
I'm not the most hardware integration/software compatibility savvy person on these threads, but I can personally attest to the fact that using the identical setup in a game, the audio in from the combo earbud plugged into the AUDIO OUT jack worked. Just for the doubters out there, I'm inserting a screenshot of audio in/out options and successful testing (whispered under the desk into the mic and got recorded feedback verification of working input).
Maybe based on this we can figure out if there is a 3rd party driver we can install that will bypass the Cirrus-latest driver failure at the OS level and not just ingame.