I managed to reattach mine a couple of times. It can be frustrating but it can be done. You just need to take your time and "feel around" with the shaft that is attached to the handle. Once you find the mated part that is attached to the valve, just turn the shaft to reattach it.
Now for the hard part! Once you are confident that you can reattach the extension to the valve, you need to disconnect it! Put some Lock-Tite on the threaded extension and reinstall it! If you skip this step, the extension will keep coming off at the most inconvienient moment!
Craig