I ran into the same problem and I was able to fix it without getting new tubes or drilling wheels. I was only able to get the top part in, part of the rubber around the valve was sticking out microscopically. I tried again and pushed hard, while trying to rotate the valve around, and it worked. Here is something for you to try: get an electric tape or a piece of paper or sheet of plastic, and wrap it around the valve, essentially making a cone like the following picture:
[ATTACH=CONFIG]14431[/ATTACH]
This should get the rubber part through the hole.