Tom, glad you noticed the need also. Obviously, there are probably a bazillion different ways of fixing this but I happened to use what I had on hand. A small piece of rubber stall mat that I shaped with a grinder to fit the open space. Made it a snug fit with some grooves. You can get the carabiner in and out but it is a nice snug fit. Which is what I wanted. To my way of thinking this is better than milling a hole, because the carabiner would still be loose.
Very similar to the fitting on the Pirana.
Dave