Please try to understand that we are not trying to put you or anyone else down or start a flame war when we correct erroneous statements.
You have to understand that unless a thread somehow gets deleted it will virtually be around forever. This means that in the future someone with a similar shield who is having trouble with the keypad part may stumble upon this thread. He could read your unqualified statement that "No extra libraries are needed for the buttons" and not realize that unless the code required to deal with the pushbuttons is included in the sketch then a library is precisely what is needed.
Similarly your recommendation to use a constructor with seven terms in the argument (
LiquidCrystal lcd(8, 13, 9, 4, 5, 6, 7);
) is just plain wrong for that shield, for many other shields, and for the circuits used with most LCD tutorials that do not use a shield. In certain circumstances it could cause a sketch to work improperly and in others it could cause component damage. In yet some other cases it will have no effect but I still can't see how it possibly could have helped in yours.
Don