How do I shrink the aspect ratio on my xbox 360?

I have my xbox 360 plugged into a sony wega widescreen television (model KV-30HS420) using the component cables so i can get 720p. However the edges of the screen are cut off on the top/bottom and left/right by about 1-1.5cm. It appears that the TV is able to sense a widescreen signal because it does not allow me to change the screen size like usual (Full, Wide Zoom, Zoom...). Is it possible to change the ratio through a vertical or horizontal shrink menu via the xbox or this specific television?How do I shrink the aspect ratio on my xbox 360?this section is YAHOO360! not xbox