SVG Output problem

[keith Luke]

I'm using LilyPond 2.12.3 to create SVG output with the command:

     lilypond -dbackend=svg xyz.ly

for various LilyPond files.  I'm getting inconsistent results as most files SVG output are readable by Inkscape, but a file is giving me a problem.
LilyPond produces the svg file but nothing shows up when I import it into Inkscape.  In all cases, the PDF files are generated properly.  

I am trying to put phrase marks around lyrics so I create the SVG file and use Inkscape to add phrase marks using the arc tool, then print the
file out as a PDF file.

Is there a way of using \markup in LilyPond to add phrase marks to lyrics so I don't have to use Inkscape?

Thanks,

Keith