I got it!

I found a cheap nashbar lightset I had lying around and mounted it on my Trek, but I didn't need all the rubber spacers that came with it, so I used them on my Felt for the superflash, and voila! I have light.

Thanks for all the suggestions. I would have used an inner tube days ago, but I don't have any bad ones. I couldn't bring myself to cut up a new one.

With the Magicshine on the front, and the Superflash on the back, I'm good to go with this bike. Now I need a cheap 'to be seen' headlight for the Trek so I can ride it to the bar. The one that came with the set won't even stay put together.

Time to search more threads!