I think you can use the same screws that were used on the old bumper's mounting area... Not too sure on that though since my buddy that works at our body shop threw the new bumper on for me and did the swap in like 10 minutes, not even kidding.
Get your trunk or hatch LED conversion kits here http://www.focusfanatics.com/forum/showthread.php?p=4542652#post4542652
"2nd Gen problems"
I've spent too long looking into the abyss. It's starting to look back.