Dear Simon,
Thanks for your explanation. Indeed the objects are simply behaving as if one were typing (say in a text editor, console etc.). Right now I'm on Windows and the behaviour is exactly the same as the Ubuntu machine. In fact it looked so trivial I had overlooked it (I admit I was a little biased by previous experience with the homonym objects in MAX).
I guess a similar scenario (many possible keys together) is games where the user may be pressing more keys at once (say a 'fire' key kept down while 'moving' keys etc.).
Kind regards, Lorenzo.