Will,
I was not talking about the phrazing, which is perfect. Exactly like a flute player would play it and with enough room to breath.
I was talking how the notes are played, which is different when you play a keyboard or a wind instrument.
The attack of a note played on a keyboard has only 2 parameters -> the note and the velocity.
When you play a windinstrument you have a 3th parameter which is the breath control and defines how the note is attacked.
Once the note plays you can simulate the breath control by aftertouch, but you can't simulate the initial attack on a keyboard.
I'm pretty sure that Qsynth understands breath control. If I remember right I've used it in the past.
It's not the soundfont that has to understand it, it's the soundfont player.
You could try this in Rosegarden, just draw a CC2 curve on the track and see how it reacts.
An alternative is what Oren mentioned, don't try to simulate a real flute
k