I bought a nice SONY HDR-XR100 camera (with HDD) and had to go all the confusions trying to get the footages on FCP 6. I tried to import the .mts files directly to FCP but no luck. I even purchased VoltaicHD which converts the .mts files into .mov so they are editable on FCP. But It works so slow. It took me almost two days of googling to find a better work-around. Finding the best answer to such simple problem turns out to be as frustrating as finding a really good porn.
It turns out that the solution is sooooo simple.
1. Connect your camera to your computer.
2. Open a project. Existing or new. Just save it first.
3. Open “Log and Transfer” under File tab. Add files using the folder icon on the upper left side of the browser window. Try subfolder if the actual folder which contains the files isn’t recognized.
(NOTE: If you want to copy the .mts files from your camera’s HDD to your computer’s HD or external one, maintain the file structures of the camera. Otherwise, ‘Log and Transfer’ won’t recognize your files. ALSO: (VERY IMPORTANT. I really learned this the hard way. 
). I suggest you don’t delete any files in your camera’s HD from your computer. ‘Log and Transfer’ won’t recognize your files anymore. If you want to delete files on you camera’s HDD, do so ON your camera menu.
I hope this helps…
