Maybe it's a question of setting G_FILENAME_ENCODING as explained in http://developer.gnome.org/doc/API/2.0/glib/glib-Character-Set-Conversion.ht...
For me it works without that (with KOI-8R encoding). However I notice that I have this variable set:
G_BROKEN_FILENAMES=1
Quoting http://www.gtk.org/gtk-2.0.0-notes.html:
* The assumption of GLib and GTK+ by default is that filenames on the filesystem are encoded in UTF-8 rather than the encoding of the locale; The GTK+ developers consider that having filenames whose interpretation depends on the current locale is fundamentally a bad idea.
If you have filenames encoded in the encoding of your locale, then you may want to set the G_BROKEN_FILENAMES environment variable:
G_BROKEN_FILENAMES=1 export G_BROKEN_FILENAMES
Try this and see if this helps.