If anyone else comes across the same issue i've had, hopefully this will help you.
My Panasonic records to SD cards in the AVCHD format. the video contents are .MTS files, stored within PRIVATE / AVCHD / BDMV / STREAM. changing the name of any of those files could result in FCP 7/X not recognizing the content on the card, rendering Log & Transfer or Import Media useless.
to archive the card's contents, i drag the AVCHD folder to a drive, then rename it according to the project. i have done this dozens of times without any problems. i have even renamed AVCHD on the card, shot more clips, and the camera makes a new AVCHD folder separating the contents. this workflow has been working flawless for about a year now. this is not a suggested workflow and is not recommended.
this past week i had a drive fail and restored the camera archive from my Time Machine backup. originally the folder i restored was a renamed AVCHD package from the SD card. L&T wouldnt recognize the contents. after hours of research and work arounds, trying everything to get these .MTS files to either be transcoded or somehow recognized, this is my solution:
in Finder, i opened a camera formatted SD card, and did Show Package Contents to the PRIVATE package. inside was an empty AVCHD package created by the camera. in a separate window i opened the camera archive that i had renamed, and dragged that into the PRIVATE package. i deleted AVCHD, renamed the file i had changed back to AVCHD, and ejected the card. i then inserted the SD card into the camera and turned the camera on. immediately the camera said something about repairing a content issue. within moments i could finally view the card's contents in playback mode. Log & Transfer would finally let me view and save the contents of the card.
if you ever change names of files on the card or after you've saved them, and have issues with FCP 7/X recognizing the media, try this and see if it works for you. otherwise, until FCP will recognize the content whatever the name is, don't change file names.
hope this helps.