light flow is the closest thing to working. you must set every individual app's sound. this is accomplished by going into the the notification menu of light flow and then picking an app like gmail, talk, sms messaging or mms messaging. then swipe over to the "sound" heading. enable light flow notification sound and adjust it how you like.
then you have to go to that app and disable the app's notification sound. this is typically accomplished by opening the app, going to setting under the 3dot pull down menu. then proceed to disable the notification sound by either making it silent or disabling notification sounds altogether.
you also must go into the volume menus and then check the box that says "control light flow notification volume independently of ringer volume." this actually couples the lite flow notification volume to the ringer volume, although i think the sentence is structured to mean the opposite. in any case you can test it by manipulating the rocker switch which will show that the notification volume will move with both system volume and ringer volume.
what an ordeal fixing this.