Sleep/meditation Vs. iPod background music

SurfGod’s audio runs in a mode that enables the sounds to persist when your device is in locked/sleep mode — this is essential for sleep/meditate mode.  Some people have expressed an interest in having their own background music when the SurfGod’s music is muted.  These two things do not co-exist trivially with the latest version of iOS unfortunately.  Do you have any ideas on this?