Have any of you guys installed the HD signature seat 54397-11 (Softail deluxe). The instructions that came with this seat are terrible. I am not able to get it to hook on the plastic ears that are under the seat at the stud bolts that hold the strap on. I don't know if the seat is supposed to hook on these ears or not. Right now mine is just attached at the tank and the screw at the luggage rack. The middle two studs/nuts are only attaching the strap. The seat wobbles a bit and I wasn't sure if it was right or not.

 

I have a similiar seat for my Heritage. 1st bit of advice take the seat back. I've had mine for about two months now. Good for short hops but the **** gets very sore after 3-4 hours. Just ordered an airhawk to help combat the problem.
Assuming you can't or don't want to take it back.

Mine attaches at the front and at the rear with a nut. The strap actually secures to the outside and not under the seat. See photo.

 

A little late to the game but this how I did it.

Mine came with a heavy leather strap with 2 sets of holes in it. First try I hooked directly to the screws under the seat with the knurled ***** there was too much slack. I thought what the heck? So I criss crossed them and it worked.
Attach one side, put the seat in the front groove, bring the strap over the seat and then tuck it under the seat and attach to the other sides ****. A little tricky but works fine. Found a video on Youtube and this is how the mechanic did it on a Softail Custom. His had one screw under the seat.
@ 2:50 you can see what I'm talking about. There may be a few different strap kits out there but this is what I had. There were no chrome ends on mine.


Here's a pic.