Maxed sizecentered pop-up

can i give the centered popup from the tutorial a Max.with and Max.height? If yes how? i tried it several times i will open a frame like
on the same concept but with an javascript it will open a max sized pop-up.
can some one help me? maybe i forgot something to chane in the actionscript
I work with MX 2004 by the way but i don’t think that’s a problem because everything works normally with a presized pop-up frame