In previous versions 1.x, you were able to adjust the volume while recording a video stream. In version 2.x, this function does not work. While recording a video stream. the volume is fixed at the last volume set (or the default volume if vlc is launched from the command line.)
For example:
W:\vlc-2.0.4\vlc.exe" -vvv --sout="file/ts:U:\vlcrecord_%TIME%.ts" --sout-display http://192.168.0.5:31344