I also have a Sony Vaio and I got UEFI working. The trick is, it is hardcoded to load the bootloader from /EFI/Boot/bootx64.efi - it does not respect the EFI boot menu.
Linux is installing its UEFI bootloader to someplace like /EFI/debian/grubx64.efi. Move that file to /EFI/Boot/bootx64.efi and it will boot GRUB. You can chainload the Windows bootloader from GRUB.
Linux is installing its UEFI bootloader to someplace like /EFI/debian/grubx64.efi. Move that file to /EFI/Boot/bootx64.efi and it will boot GRUB. You can chainload the Windows bootloader from GRUB.