And I see nothing in manuals that suggest this is possible. Yes, a lot of people have tried this and have your question but unless it's documented as a feature with how-to in the manual...
I have a "AVCHD" folder copied direct from my Panasonic TM900's internal memory sitting on my computer's HDD.
I now want to copy it back to the camera/SDHC card to view on the camera.
I tried copying the folder, into a folder named "PRIVATE" (as per the AVCHD file structure), on an SDHC card, however the camera does not see the files.
What am I doing wrong?