On Aletes, as the companionway door is raised there is a piece of plywood at the bottom on the hidden (back) side of the door that forms a stop to prevent the door from pulling out altogether. It is held in place by 4 or 5 screws visible on the interior side bottom of the door when the door is fully up. Removing those screws allows removing the stop and thereby allowing the door to be raised higher than the threshold. At that point you have access to the screw that hold the weatherseal in place. Simply remove the old weatherseal and install the new.
Hope that was clear. Let me know if you need more details.
Rock Hall, MD destination Antigua in November
How did you mount this strip? Did you have to remove the door?