Hotmail doesn't have IMAP push enabled.
I don't know how (and even if) the stock email app can do immediate notifications with hotmoil.
The only possible way would be if hotmail supported activesync. But I don't know if hotmail sipports that.
Aquamail author Kostya would know that for sure, but he will be back from his vacation in a week.
Alternatively, if your client is set to check every minute that would produce a result close to the desired one. But it Woolf also produce more drain on the battery and lots of traffic usage.