Maybe you could find a longer screw for the handlebar clamp?

In the past I did something that was ugly, but worked well. I sawed the bracket off of the mount. Then, using JB Weld, I glued the rest of the mount to the center of my stem. I never had a problem with it, it was just ugly. JB Weld is very strong (other epoxies would probably work). But, you'll never be able to move your computer to another bike, and if it breaks, you have to remove the epoxy from your bike, which will take the paint off with it.