Awesome, it worked, thank you.
And actually i found another way to get it working without having to rename or move files: on title screen, go to options, select the one which is about detecting the CD. When the game asks you to insert the CD, return to emulator menu, load the iso file and this time it will return to the game without resetting (!). Press the button the game is asking you to start disc recognition, then enhanced soundrack is automatically started.
Your way is simpler off course, but i think it was worth mentionning it worked this way too, got my head scratching on that a few hours before noticing the option menu.