coda placement problem

[Kenneth Teh]

I'm having trouble placing the coda symbol.  The
closest I've come to what I want is reproduced below.

        g2 c,2 | \mark \markup { \small \musicglyph
#"scripts.coda" }  % mark jump point
        r8 g'8 af8[ g8] ef4 d4 |
        c1~ |
        c1
        \once \override Score.RehearsalMark
                #'break-visibility = #begin-of-line-invisible
        \once \override Score.RehearsalMark
#'self-alignment-X = #right
        \mark \markup { \small { "D.S. al Coda" } }
        \break

        % coda 

        %\once \override Score.RehearsalMark #'extra-offset =
#'(-3.0 . 3.0)
        r8^\markup { \raise #3.0 {\huge { \musicglyph
#"scripts.coda" } } }
        g'8 af8[ g8] ef4 d4 |
        r8 g8 af8[ g8] ef4 d4 |
        r8 g8 af8[ g8] ef4 d4 |

which I gleaned from reading your archives.  The
problem is that the \raise does not produce an effect.
  If I rewrite the first 2 lines of the coda section
as

        \once \override Score.RehearsalMark #'extra-offset =
#'(-3.0 . 3.0)
        r8 \mark \markup { \huge { \musicglyph
#"scripts.coda" } }

then, the "D.S. al Coda" string in the previous bar is
affected, not the coda symbol.

I've also tried attaching the "huge coda" to the bar
line, but this wipes out the "D.S. al Coda" string. 
I've read you cannot stack 2 rehearsal marks.

I prefer the rehearsal mark to a straight text markup
because I am scoring something for multiple
instruments.  I write the same rehearsal mark for each
instrument so that when I generate the parts, the
codas are reproduced for each part, but in the combo
score, I see only 1 coda.

A final comment:  Note that I add a break just before
the coda.  This is because I want the coda section to
start on a new line.  There is a small coda in an
earlier bar to mark the "jump" point.  What would
really be nice is to put the "huge coda" right above
the clef at the beginning of the line so that the coda
section is clearly marked.

I'm running Lilypond 2.6.4 on a Mac OS X machine. 
Btw, it's a great application.  I discovered it about
2 weeks ago and have been spending my evenings playing
with the software.  Great fun!
I write software for a living myself and it's a really
nice piece of work!!

Ken