I have loaded a sample file from the Humax that you can download from https://public.me.com/dorianmwiskow
. . . this link is only good until 30th June, so please confirm once you have downloaded it.
If you use VLC to play it back [on either OSX or Windoze] you will be able to play it back and switch sus-titles on and off . . . but, when I use oPlayer on OSX I am unable to switch off the sub-titles and they appear to be incomplete and poorly displayed by comparison.