[Regin Toftegaard]

You actually can work with XAVC-L files in FCPX. However, it requires a specific routine in order to make run smoothly.

First, you need to be running Final Cut X 10.2.1 and your Sony PXW-X70 needs to be running on firmware version 2.00.
It isn’t possible to import directly from the SD card, as the folder structure on the card somehow confuses FCPX. To make it work, you have to take the folder “XDROOT” on your card and copy it into an empty folder on your hard drive. It is very important that nothing else but the XDROOT folder is in this new folder on your hard drive.

Once this is done, you will be able to import the footage from the folder you created on your hard drive into FCPX.