You nailed it -- my headphone jack is a one way street. Meanwhile, in desperation today I came up with another solution: I recorded the Casio song data into my Marantz desk top recorder, downloaded that file to my laptop and then into Audacity where I boosted the volume (which was really low for some reason), exported that to my Dell desk top as a wav. file which I can now convert to mp3 and send to my band members! Where there's a will...
I checked out your link to the U-Control unit and I'll probably pick that up. Thanks again!