I deleted (but saved a copy) of fond.wav, you find it in Histwar/sounds/ambiance. I converted the final movement of the "1812" overture to a .wav file, renamed it fond.wav, and put it into the above file. Now I have the perfect background music in 2D mode.
You don't have to be genius to convert files. If you have an mp3, mp4 or wma music file, google "online free mp3 to wav converter", you will get loads of sites, you don't even have to download a program. The online ones are easy, just upload your music file and it converts it to the wav, then download it back to your computer.