For those who are interested, the following files are needed to convert the game into a different language:
Booth.iff - text in the booth like the welcome screen
Dani.big - the audio of the ships computer voiced by Dani Behr
Gameflow.iff - text that is displayed in menus (e.g. load game), pad (name of the transits, e.g "customs", "You Are Here"), planetary interior (e.g "exit to transit", "enter booth"), text between fmv's (the text of the 2 plot-choices), text of the various commodities, weapons, ships, systems, missiles, Bulletin board text "Reward"/"Tons"/"Hire
Isets.iff - the audio that Lev Arris speaks between the FMV when the player has to make a plot-choice
Mission*.iff (0-9,m,r) - the text of the missions and diary entries
Pad.iff - the text on the P.A.D. like the "exit" button and the background images.
Speech.big - the voices of the different pilots
P.S.: it would be cool if someone with a French (or other language) version could post the pictures here too.