Confused about how to "expose to the right" in Av mode...any help?

Ok, I was out with my Mom and sister the other day and it was the afternoon in some harsh sun, so I was getting some weird metering results and I was trying to expose to the right a full stop. On the top of my 40D, I would hit the Metering/WB button and I used the dial by the shutter button to adjust the exposure, but I got no results.

However, when I use the dial on the back and make the same 1 stop adjustment, it worked. What was I doing wrong or was I just using the wrong dial? But if so, what does the dial by the shutter adjust and why was it showing it on the top screen of my 40D but didn't seem to do anything.

The dial on the top changes the aperture you use in Av. The camera will still assume a "normal" exposure. The dial on the back is used for exposure compensation, which is what you need to do to offset your exposure from "normal"

Thanks for the reply Jon. I think I actually figured it out. I was pressing the ISO button and after changing ISO, I was then adjusting the Flash +/- and NOT Exposure Comp. I was simply changing the wrong setting.