Using the break-alignable-interface (aligning RehearselMark)

[Werner]

Hello,

I tried to get a left-aligned (or offset) RehearselMark.
This could be above a dashed bar-line (or above the first note after this)
but
neither
\once \override Score.RehearsalMark #'break-align-symbols = #'(NoteHead)
\once \override Score.NoteHead #'break-align-anchor = #15
\mark \markup {C \magnify #.9 \italic {frei im Rhythmus} }
\bar "dashed"

nor
\bar "dashed"
\once \override Score.RehearsalMark #'break-align-symbols = #'(BarLine)
\once \override Score.BarLine #'break-align-anchor = LEFT
\mark \markup {C \magnify #.9 \italic {frei im Rhythmus} }

don't work. 

Who can help?

Thanks

Werner