GL-MT300N-V2 (Mango) + MR Webcam: no audio support?

Title says it all: can get a fluid video stream at 1280x720 30fps but there is no audio from the microphones of the MicroRouter USB webcam. Any pointer on how to enable audio as well?

Is it a USB webcam and you are streaming it using mjpeg-streamer? It does not support audio.

USB webcam: yes, the GL.iNET one.
Streaming as on the docs on the GL.iNET with mjpeg-streamer.
Will be possible to run along a USB audio adapter in order to stream both Video and Audio? Need both and standalone IpCams use too much compression for the audio part (voice is full of artifacts).

The mjpeg-streamer just does not support audio. No way to do it.