After a bit of experimenting, I've worked out how to do this. Put marble.themerc
in .../apps/kstyle/themes, the pixmaps in .../apps/kstyle/pixmaps and copy
.../config/kthemestylerc from a older version of KDE. It's probably possible
to just add the appropriate entries for the marble style to the existing kthemestylerc,
but I haven't tried this because the one in 3.4 is empty by default.
Michael