Great tip. I consider Unarchiver to be an essential Mac utility. I've been using it for years and it's still one of the best freeware programs around. Just to note, the current version of Unarchiver (2.2) includes XAD libraries that work beautifully with .7z files but some earlier versions (1.x) do not work well with 7-zip. There should be no problem as long as you are using Unarchiver 2.2 or later.
To be crystal clear for Mac beginners, once you extract the *.7z file to an *.iso file on your desktop, drag that *.iso file onto Disk Utility's icon (the disk with stethoscope icon in the Mac dock). Disk Utility's icon will bounce a couple of times while the program launches. Select the *.iso file below the gray separator bar in Disk Utility's left pane, insert a blank DVD, wait a few moments for the blank DVD to be recognized, then hit the black-and-yellow burn button. After Disk Utility completes the burn, it will typically spit out your newly burned disk (unless you clicked the "Mount on Desktop" option.) Trying to play this disk in your Mac's DVD player is pointless; it's designed for Blu-ray players.
Once you've confirmed you have a working AVSHC 709 disk in your Blu-ray player, you can safely trash the *.iso file. Keep the .7z file around if you want to make further copies in the future.
I hope that helps AVS Mac users. It really could not be simpler.