Carl,
I've used a bear vault before. Luckily, it turns out that no bears attacked, but no bear could possibly open it. A bear could paw it around and maybe even steal it, but he cannot open it.
I think the bear vault was just inside at the top of the backpack, or outside strapped on the bottom - either way, you'll want it readily available for snacks.
Bear vaults also function well as stools when on the trail.
Hope this helps!
Woody