How do you align a "segno" over a Repeat Sign?

[joelinux]

% ****************************************************************
% Beginning of the actual notation code
% ****************************************************************     
% Melody - Line 1
        R1*12 \bar "||" \break
\once \override Score.RehearsalMark scripts.segno #'extra-offset = #'(-2.0 . 
0.0)
\mark \markup { \musicglyph #"scripts.segno" } \bar "|:"

Right now the Segno is to the right of the Repeat sign
Ideally I would like it over the top.

I don't know the correct terminologly and after researching the docs, I haven't 
come up with anything either.

Terminal Output:
address@hidden:~/LilyPondProjects/08-TheOneThatGotAway-T-4AD> lilypond 
TheOneThatGotAway.ly
GNU LilyPond 2.6.5
Processing `TheOneThatGotAway.ly'
Parsing...
TheOneThatGotAway.ly:30:36: error: syntax error, unexpected STRING, expecting 
SCM_T or SCM_IDENTIFIER
\once \override Score.RehearsalMark
                                    scripts.segno #'extra-offset = #'(-2.0 . 
0.0)
TheOneThatGotAway.ly:109:8: error: errors found, ignoring music expression

        <<
error: failed files: "TheOneThatGotAway.ly"
address@hidden:~/LilyPondProjects/08-TheOneThatGotAway-T-4AD>