Thanks lisa !
I'm now able to try and use the ATI tools (thanksfully there's a GUI provided) with that exporter.
I also have Melody from Nvidia.
Did you try it already ? If yes which one do you think is the "best" : NormalMapper from ATI or Melody ?
I do have an Nvidia Geforce FX5200 (yep an old card
) if that makes any difference (does it ?) ?