How to get the nuts/screws? out
Try to grab them from inside the trunk with vice grips. They should be fairly loose to start with.
They are called Trident screws. I'm not sure, but I think they are #10. They might be #6 too. Here is a link to the #10 installation tool for $8.51.
http://www.tannerbolt.com/default.aspx?page=item+detail&itemcode=10TRI