No AVCHD lite support right now. Maybe, some weeks months ahead, maybe.
Studio 12.1 does not offer full support of MOV 1280x720, H264, 60 fps video either. Preview is almost impossible, and effects, transitions, or overlays cause burn failures. However, if I set up the project at 1280x720, assemble the plain clips without effects, and create a HDD disc image intended for Blu-ray, using the BD-MPEG output option, the resulting mts stream file in the BDMV folder can be dragged to the timeline, edited, and previewed. Studio reports that it is 59.9 fps, even though it reported the original clips as only 29.9 fps. You might try this with a few clips to see if this also works with AVCHD lite. Whether an MPEG2-1280x720 export option would also work, is worth a try. Your results could be an important bit of news.
Did you use your Lumix FT1 underwater? Did any vapor subsequently appear on the inside of the lens chamber? Are special procedures and cautions necessary to change the battery or SDHC card after submersion? Does the mic register "gurgling" sounds when you shoot terrestrial shots afterwards? How about if you are in the surf and intermittently above or below water? Must you pick the underwater, no-sound mode, just to be safe? What happens if you go below 10' (3m)? What is the typical visibility range in the waters off Wollongong?