Help Pop-up notifications don't pop while phone is locked

[goatt]

Hi all. I use Handcent (and before that SMSPopUp) and I want the notifications to pop up on my screen (not my notification bar). When I click the 'test notification' in Handcent it works the way I want it to but once the phone is locked it doesn't pop-up, just the notification in the bar shows up. Any ideas?