proper placing of chordnames re: alternative ending brackets

[John Sellers]

Newbee question:
I was doing a simple lead sheet with repeats and alternatives and had 
trouble with the chordnames being above the alternative ending brackets 
rather than between the brackets and the staff, which is the usual way 
of doing lead sheets.

I got some help which lead me to a solution to this problem posted in 
Feb., and after playing got part of it working:

\score {
 \notes <<
   \context ChordNames {
       \set chordChanges = ##t
       \harmonies
   }
   \context Staff = one \melody
   \set  verticalExtent = #' (-1 . 3.5)
   \set  minimumVerticalExtent = #'(-1 . 1)
 >>

 \paper{
%     \translator {
%            \StaffContext
%            VoltaBracket \override #'padding       = #3  %pts
%        }


The part that is flagged out is an exact quote from the solution 
posting, but the translator escape is not recognized by lilypond in my 
case.  What should I do to get the VoltaBracket padding modification to 
work?  Translators are completely beyond my newbee experience.

Thanks,  John Sellers, fiddle player, violinist, and Former Smalltalker