You probably need to put the ignition in the dash and get an earlier steering tube and maybe shaft too,
The VW tube is larger diameter than the bus tube. So, you need a larger opening in the switch housing.
I used a drum sander on the left side containing the switch to enlarge the opening and an early Beetle right side half.
I originally tried to make a smaller tube out of copper tubing. I had to enlarge the top end to use the VW bearing and that made it more difficult to fit the bus switch housing.