The only reasons to keep the outer tube, that I can think of, are;
(1.) decorative - it covers up the steering column with a nice decor tube and;
(2.) it also provides you with a handy-dandy directional switch mounting point.
Not having it means that you have to find another way of mounting your directional lever (and maybe horn wiring, too)
BTW: A VW Steering column is just about the same size as a chromed, telescoping fork mount on a motorcycle - check around.
gn