OK i found it "how".
1. You need StereoTool Standalone installed
2. You also need Virtual Audio Cable(s) installed
3. Go to Options in Raduga and in "Mixer" Option select "StereoTool.exe" from Stereo Tool standalone
4. In DirectX Plugins select Output Device Virtual Cable 1 -> Press OK
5. Press X while in Raduga to call StereoTool
6. In StereoTool Select Input/Sound Card Virtual Cable 1
done!
PS:
In my opinion this is worst player for any purpose. For example, Winamp with few plugins is always better choice!