My apologizes I was at the boat on the weekend and removed the center line as well and reinstalled. I forgot my camera... It's hard to tell from your photo but it does look similar. It's hard to explain, it took me two years to figure it out, but once I did it's pretty simple to do. I reinstalled with a music CD pushing the material in the track and rolling the cd back and forth. I push the scrapper into the slot where the flat liner meets the first crease (hope that makes sense). I pry a small portion out with the edge of the scraper and pull out with my fingers. My boat is a 2005 and the headliner is in excellent condition and could easily handle me pulling on it. Your picture looks like the material is a little cracked, so be careful pulling it out. I found it best to start in a corner, easier to pry a piece of material out. Hope this helps some.
I found most of the fasteners for the deck hardware needed tightening once I got the liner down.