I can see its been a couple days or so., but for those with USB boot issues.
If you are stuck with just the 1 USB port and cant boot to USB, nor prompt the boot popup menu or when using a hub, you need to turn off UEFI bios. This then lets you select a boot order in the more traditional manor, putting USB KEY first. This then saves the need to even tell the machine what device to look for. Mine is now up and running on our corporate build of Windows 7 x64. I'm sure this happens because the USB's were built with a bootcfg that doesnt support UEFI(?!?!).
Once out of UEFI mode you also get on screen touch buttons on the post page, seems a little counter intuitive to have more functionality in the older BIOS but hey, from which you can access the boot menu etc.
A colleague had looked at it for a long time and been through things with Panasonic to no avail. They were going to send an engineer out. Not sure how they didn't think to suggest it may be a BIOS compatibility issue.