Screen adjust for games that don't have the option

[pedrolito]

Hello everybody!

I'm french and i'm actually trying to "rebuy" all the games i've already got in PAL version, in NTSC (US or JAP).

I finally got my hands on the US version of "Final Fantasy X", but the guys at square forgot to put one very simple option into the game : the screen adjust!

When i launch the game (with hdloader, i don't have a modchip), the screen is not centered, it goes way too much to the top and a little to the left (CRT TV with RGB cable). So what i need to do is correct the offset (X and Y axis) so i can center the image.
I think there might be a way to "patch" the iso i made out of my original, by changing some values with an hex editor, but i really don't know how to do that kind of thing. Also, i don't want to patch the game from NTSC to PAL, since i want to keep 60Hz display.

Can somebody please help me? Thanks.