Importing to FCPX from Sony Camera

Question

I am trying to import 1080/60P clips from a current Sony camera into FCPX.
I am well aware of the tradeoff of size vs editing ease between AVCHD and ProRes. In this case I have hundreds of clips, most of which will be trimmed drastically if they are used at all. So I am hoping to do a rough cut in native format, then transcode that rough cut for final editing and cleanup. Should be a big saving in disk space. I have a new quad core Mac that should be able to play the native clips quite well.
I already have an archive of the camera files on a Firewire 800 drive. I was hoping that FCPX would be able to import it by reference, creating little wrapper .mov files. However when I try to do that, I get a message that the folder containing the video cannot be imported. (It does offer to import the folder of stills that is part of the same file structure).
If instead I choose Import from Camera, FCPX happily ingests the video files but from the size of the .mov files it creates it is clear that they are not references but copies of the camera originals. That makes complete sense for initial import of an actual SD card or USB-mounted hard drive, but I really don't want another 50 GB of files filling up my drive.
If necessary I will use that process then delete the 50 GB of originals (I do have another copy on a second drive). But I am hoping that there may be a way to create reference wrappers around the files I already have on my drive so that I can work with them where they are.
I am interested to know why FCPX behaves as it does, if anyone knows. For example, are audio and video multiplexed differently in the camera archive than in the .mov files that FCPX creates?

Answer 1

Thanks for the quick reply.
Camera is HDR-PJ760, which has proved to be absolutely amazing for handheld shots in difficult conditions. Many of the shots in this project were taken from a boat on the ocean, where a tripod would not have helped. All using the highest available quality settings at 60P. You can't get back quality thrown away in the camera. (Yes I know that the high compression in AVCHD is in fact throwing away a lot, but there is always some tradeoff to get a reasonably compact handheld camera.)
I am guessing that the camera files are muxed, and that is why they cannot be used directly. If that's the case, I will just have to put up with the conversion step.