Is it possible to give a certain name to a subtitle file, to make the Philips DVP5140 DVD Player recognize the respective sub as being in a certain language?

See, I thought if I name it something like: "Van Helsing (2004).pt.srt" (for example), the player might see it as being in the Portuguese language. But no.
"Van Helsing (2004).en.srt", "Van Helsing (2004).pt.srt" or "Van Helsing (2004).fr.srt", the subtitle still shows up as "Subtitle: 01/01 Others". (- Not "Subtitle: 01/01 English", or Portuguese, or French, as I expected it might say.)

I thought a specific way of naming the subtitle file might make DVP5140 recognize it as being English, or French, or some other language. That would be great.

Does anybody know how to tweak this, if it's tweakable?