Fading CocosDenshion

Is there any way to smoothly fade cocosdenshion volume (for background music and effects)?

This would be really helpful, but knowing when a sound fx ended playing would be perfect, so we could have intro/ending sfx. Right now there’s a SFX in my game that needs to have an intro and ending sound, as it has an inner loop playing while the player is touching the screen, but I just can’t do that without knowing when each sfx has ended…