Thanks for your asnwer, but not exactly the same, or at least I don't know how.
I mean, following the Kovid's info, as I told in post #3, I got Calibre not seeing my device, but I admit that surely I did something wrong and that really works.
But the pint is: what happens if you have more than one device for same brand&model and you want them to work in different ways? My case: my wife's and mine are both Kindle Fire. Hers is an untouched one. Mine is 'upgraded' and now work as and Android 4.0 tablet. But Calibre detects both as the same kind of device.
That's because I was talking of the idea that we could have some sort of BD with a brand/model <-> single device (an item, not a model), so we could control the behavior of every single device.
Anyway, thanks for your answer.