Sorry to dissapoint you, but I have no clue what kind of code you should use in QT to use the same buttons that are used for example in calculator application for numbers.

I saw another applicatino on extras-testing which used those buttons successfully, cannot remember the name but that app added four application shortcuts to the menu that pops out when you tap status bar. Hopefully someone with knowledge will help you out with this since those blue buttons are pretty horrible in my opinion