lchiu7:NZtechfreak: No, you can't back up larger than 4GB, since the PS3 won't work anything that isn't Fat32 formatting (and thus limited to 4GB). I've been splitting my recording times and stitching the files on my PC as a workaround.
Correct me if I am wrong but I thought once you moved the video file from PlayTV to the regular storage area of the PS3, the DD audio on TV3 gets lost and you are left with only the AAC audio? If that is the case then that makes using PlayTV to record and archive content less than useful.
For my part I only use it for TVNZ because it handles AAC-HE LATM audio nicely - for TV3 I use a PC with GBPVR.
You have it around the wrong way, TV3 exports to the XMB 100% in DD all the other channels that are in AAC/AAC+ audio is lost, this is a known bug.
One of the better PlayTV info sites is http://whirlpool.net.au/wiki/?tag=ps3_playtv very up to date.