Microphone passtrough

Hello, 

we are using DELL 3040 Wyse ThinClients and trying to passtrough an USB-Headset. The speakers are working but the Microphone doesent show up. The Microphone + Speakers are shown on the ThinClient, but after the RDP Connection is build up, only the speaker show up.

I cant see an option to activate the passthrough in the Wyse Management Suite. I found an other Topic (https://technicalhelp.de/topic/no-audio-or-microphone-in-rds-session-desktop-on-wyse-3010/) In this Topic i should add a line "SessionConfig=RDP EnableRecord=yes" in a wnos.ini file. But i cant find this File on the server. 

If you need more Informations please let me know. Thanks