Some cameras don't have lugs to attach a split-ring, but they have recessed rods or posts. A string strap works best for these cameras.
The attaching string is the same heavy-duty waxed cord that's used for the wrapping. The string is surprisingly strong and attaches to the strap securely. Check out my strength test for a better visual. Make sure there are no sharp edges where you would attach it. If there are, you should use a Lug-mount wrist strap. You can also check out our page "Which strap do you need?" for a better visual.
I've also included a black rubber o-ring to each strap so you can reduce the strap opening for a more snug fit.