On Windows you need to re-think your methods. For example I had to implement a DLNA server and DLNA device to accomplish this.
I'm sure you understand Windows well enough to figure out why your initial setup failed.
I want to ouput two tracks to two output devices. One output sound device is an external USB sound card (M-Audio interface), the other is the internal speaker/headphone of my laptop.
I have two wav files and I want to load them into a program and press the play button and then hear one track via the speaker/headphone and another via the M-Audio interface. I looked at many different programs, but to my surprise I din't find one where I could load two files, set one to output device 1 and another to output device 2 and hit the play- button.
The closest I got was loading two files and playing them on one device, then stop playback, switch to the other device and resume playback. But I need both audio devices to playback a different track simultaneously.
Any help appreciated!