OK. Right now I have a perfectly working dual boot laptop with Ubuntu 12.10 and Microsoft Windows 8 (both in UEFI mode). The disk is partitioned in GPT format (needed by Windows UEFI installation and preferred by me).
What I would like now is to enable a function of the laptop (called ExpressGate) that allows me to boot an different OS from a special button. The function works finding an special file in a FAT/NTFS partition in a MBR disk, and I know that works with hybrid disk.
But it's impossible to me to make Windows boot from a hybrid partition (using the gdisk tool).
Someone had any ideas?