Well, it appears that this MapRawKey example code was a lot more useful than any explanation i've read on the subject, even though i had to compile it and then read the generated asm...
Of course it didn't do the exact job I wanted, but i was able to properly use it in my system framework (you remember that thing Thorham ?), and get satisfactory results (to my greatest surprise).
Now IK is using it and a new version is there for testing :
Remember the keys are now mapped "correctly" (?) so the M for music on/off is no longer necessarily the one next to the "L" key
Another thing is that it's probably not a good idea to make a floppy version (or a whd slave) from it, as it would then use a fixed keymap again...
Even though I've made my own tests, I'm not exactly a good tester for this kind of game, so i may have missed something and added a few more bugs
Anyway i dare to hope the poor mites forced to use these dummy qwerty keyboards will be satisfied