PS3 - Can't change audio on VOB files

I did a copy to my HDD of movies kids are watching over and over. Since we are french speaking and one of my kids is learning english, I keep both french and english track.

The proble I have is that since english is the language by default, the movie start playing in english, but I can't change the audio "track" to french. I can do it on my iTouch with a DLNA app, so I know the file is fine.

For other formats, such as Divx, I can change the audio track.

Thanks.

[Illico]

When a file is transcoded, only the first video and audio tracks are delivered.

When a file is delivered in native format (supported by the device), all tracks are presented (video/audio/sub).
But to select the proper track on native format stream, it's renderer device dependant.
For example with Sony Bravia TV, change audio track on VOB files is not supported.I suppose, it is the same for PS3.