I just reread my initial post and need to make a correction - the frame is chromoly. I was momentarily confused - must be the kids ;-)

I would LOVE to be able to use a clamp on cable stop - I haven't been able to find anything big enough for the tubing on this bike, though. I have already emailed Co-motion to see if they have any suggestions, which hopefully they will respond to after the weekend is over. As for Andy's question about how this happened, I'm not sure. The bike has been very lightly used and garage stored. My boys lost interest in riding the tandem with me much younger than I thought they would so it has well under a thousand miles on it. My daughter is just reaching the age where she can ride with me, but when my wife took her for a ride it came back broken. She said it "just came off" as they were finishing up the ride.

Thanks to all of you for your input!