Hey Norm - would you be willing to try removing the covers on your rail feet? If you ease the sides outwards with a sharp right-angled pick, they should just lift off.
I've had a couple of replies on other fora, everyone who has replied from North America (you're the fourth) has said the same thing - no movement - one guy in Australia says his move.
Based on what I'm seeing, it seems that US market vehicles don't get the same rails as my car has - I suspect the US market gets rails with plastic feet, whilst mine has a cast alloy foot, and that may be a significant difference in how the rail is attached to the foot.
The current plan is to drill through the underside of the rail and the feet and secure them with screws & nuts - the screw heads would only be visible if viewed from the right angle.