Ingrid, I looked at that site’s main page, and it says they’re doing work on it, so some pages might be down.
Wenda, this pattern looks really easy to modify. Do a gauge swatch to figure out how many stitches you need for the chest circumference, and cast that many on and knit the rib like the pattern calls using the normal needle size for the yarn you have. Then, just switch to a needle a few sizes larger for the stockinette body. I’d think the increases they use would work, but I’d measure every few inches to make sure, and fudge it around if necessary. Then for the straps, pick up, instead of eight, enough to make them as wide as you want, and you can still use the same directions for them. Just make sure to pick them up along the top so that there’s enough room in between, and make them longer than the original pattern.