Calendar Events (Alert on date of event) Question

Just had a quick question about Calendar Events.

When you set, lets say a Birthday on the Calendar and set it as an "All day Event" & set the alert to "On date of event" what time does it notify you at?

Should I expect to get an alert tonight at 12am stating "Birthday!!!" or will it notify me at a decent hour? lol

(yes I know I can change it from an all day event and set it for later in the day but that's not my question)

Thanks!

EDIT: 08.14.08
For those who don't know ; The iPhone woke me up at 12am letting me know it was someone's birthday today. Pissed me off a little but I was expecting it. Even though I have sync'd with my iCal (Osx) and had set in the options that my work day starts @ 8am.

This little problem will hopefully be addressed sometime in the future. Until then it's best to not set an alert "On date of event" but as a specific time. *sometime after you're usual wake up time*

Unless of course someone has a fix for this.

For those who don't know ; The iPhone woke me up at 12am letting me know it was someone's birthday today. Pissed me off a little but I was expecting it. Even though I have sync'd with my iCal (Osx) and had set in the options that my work day starts @ 8am.

This little problem will hopefully be addressed sometime in the future. Until then it's best to not set an alert "On date of event" but as a specific time. *sometime after you're usual wake up time*

Unless of course someone has a fix for this.