My husband and I did a quick bathroom update--painting and changing out the builder hardware etc. All of the new hardware went up so easily except for one pesky robe hook. The placement is on a short wall where the builder's ceramic hook had been. As I had drilled the pilot holes for the wall anchors I realized that there was a duct behind it. I thought I could be creative and cut down two screw in wall anchors w/ shortened screws. This actually did work--for like a week and then the hook ripped out of the wall robe and all. What can I use to secure the hook to the wall. I want to use the hook that matches the other hardware so no command hooks or changing the hook placement. There has to be a way to attach something to a wall when there is duct work behind it. I have about a half inch of space including the drywall. Help, please . . .