Thanks for your explanations, SteveThaiBinh, I've found a mod which seems to be good.
But now I get a little problem : how to install this mod ?
The only help at my disposal is the following one :
"The first thing you should do is check your SWKOTOR2 directory for an "Override" directory. If you do not have one create it using File-New-Folder in Windows Explorer.
There are four different sub folders include in this mod, one for each difficulty setting. Depending on the difficulty level you want copy the file "k_ai_master.ncs" from the appropriate sub folder into your SWKOTOR2/Override directory.
As long as this mod is installed it will be active on every save game. It is not necessary to start a new game.
If you want to switch difficulty, you have to copy the file "k_ai_master.ncs" from the different sub folder. The new settings will not be in effect until you move to a new area."
I don't understand what I really have to do with four FOLDERS (one for each difficulty), each containing one DIRECTORY. Moreover, I get a folder entitled "source scripts".
Must I add all this files in the sub folder named "override", which is situated in kotor2's folder ? Do I only need to add all the directories without their folders ?
Please HELP !!!!
P.S. : my dictionnary doesn't mention the existence of the expression "check something for something". I've never read that before...