there have been topics about it on the mailing-list concluding that pd needs another implementation of [key] object for playing note on and note off, [hid/keyup] can help to do this, like in examples proposed in here:
actually I got that quite easily sorted by storing the current value on a table and checking it before allowing new notes in (can send that at some point, it's very easy). What I meant was if there was a patch with a GUI that already has the interface prepared to look like it's ready to play some notes.
João