Issue with themeresource file names

I am facing problem with Themeresource filename with spaces,

Link help = new Link();
help.setIcon(new ThemeResource(helpImage));
help.setDescription(“Help”);
help.addStyleName(“icon-only”);
help.addStyleName(“borderless”);
help.setTargetName(“_blank”);
help.setResource(“a b.html”);

please suggest.