According to BH, it'll only work with cameras that have the grip.
So, I imagine you'd be fine if you had the Canon grip for the 350.
Still, I'd probably prefer the Optech strap we have at DSLR Users since it works on pretty much every camera regardless of grip or not.
EDIT: Doesn't seem like it's a
user friendly product for installation. It's a strap for Christ's sake. It shouldn't be hard to "install".
That said, it looks as though you need some sort of notch or hole on the bottom of the camera to be able to tie this under, similar to the phone straps that come with mobile phones that loop themselves. So if your body doesn't have that, you're hosed.