OK, will check the file. However, note that WinCDEmu wil only mount the ISO tracks of such images. Making a kernel-mode mp3 decoder would be a very complicated (and useless) way to achieve the same result, as if you open the mp3 files in your favourite player 😉
As for Windows 7, some people like it, some don’t, but the goal of WinCDEmu is to make image mounting really easy. So, as long as a particular OS version is popular, WinCDEmu supports it 😉