How to change the position of an expressive mark relative to a beam in another voice

[Robert Blackstone]

Dear all,

I need some help with a problem that I have not been able to solve up till now.

The composer, long dead, some of  whose piano music I am reengraving, wants me to write this (see https://dl.dropboxusercontent.com/u/512573/FileChute/Screen%20Shot%202017-06-23%20at%2011.19.08%20.zip).

In this particular composition this figure occurs many times in slightly different forms but the main problematic element for me is the extra large marcato mark halfway between two beamed notes, above the beam. The best result I have been able to produce can be seen here (ignore the fact that there should have been a half note at the position of the 8.-note - that does not give a  problem)

%%%%%%%%%%%%%%%%%

\new Staff  {

       \clef bass

    \time 4/4   

   

          <<  { \tuplet 33/32 {\omit TupletNumber \override TupletBracket.bracket-visibility = ##f s32 \set fontSize = #4.5 \once \hideNotes g'1^^ } } \\ {\slurUp \unset fontSize \stemUp c'16 [es'8.] s2.}   >> 

          }

%%%%%%%%%%%%%%%%%

Somehow LilyPond insists that the beam remains on top, or that the marcato mark remains below the beam. 

Any suggestions?

Thanks in advance.

Best regards,

Robert Blackstone