[2Lr] Bremse96_HF

Hello, i already detached the On-Ear-Headphones of the Vive Cosmos, now i just try to connect my Headset Microphone and Audio to the Cosmos, my Sound works but the Microphone is still the built-in. Does anyone know how to get there? I have a 2 to 1 adapter for the 3.5mm jack.