As you know, these strings are saved in a .conf file, default.conf for me (in items caption=something).
Do you know why has been made this choice ? other strings are translated on the fly, but why not these ones ?
Apparently, they are recreated at the next C::B start, if you delete the default.conf, but this is not a good solution because you loose all other config adjustements !
May be you can recreate those strings, and only them, keeping all other settings, when you change the interface language.