Which group do you ride in? (Just trying to get an idea of your ability).
I went from a 600 to a Mille, kept it for 2 years and now ride a GSXR1000 K5, which I honestly think is better at everything compared to the Aprilia, except for pillion comfort!
Anyway, with the Mille you have a lot of engine braking, so first thoughts are that you can never coast through a corner- you must always, always be on a neutral throttle or accelerating.
And without teaching Grandama to suck eggs, i went riding on Sunday for about an hour with a 'friend' of mine who is a new rider. He is very fast already but his technique is shocking- no body movement, doesn't weight the pegs etc etc...
Can you post a photo of your cornering technique? Be good to see how you look on the bike.
PS I'm not that fast myself (fast group but not quick enough to race), so this could be a case of do as I say, not as I do!