Rear sling attachment options for a Sig 556 Classic

[mriddick]

Anyone have a good way to attach a rear sling to a 556 Classic's lower in such a way that it works with the stock folded as well as extended?

[AK-J]

I plan on getting something that attaches to the ring on the back of the receiver.

[mriddick]

My classic has no ring, do you have a picture of the ring? I'm hoping someone makes something like a rear pivot pin with a sling attachment point but I've not found one on line in my searches. Oddly my 522 has a swivel stud at the rear of the receiver that works great, I wish the 556 had one in the same place.

[AK-J]

Please excuse the terrible camera phone pics: