When creating a Boot Camp virtual machine, you can set its configuration. There may be two types of Parallels Boot Camp configurations:
The default Boot Camp configuration allows using only one Boot Camp partition in a Windows XP or Windows Vista led. The custom Boot Camp configuration allows using several physical partitions grouped as Boot Camp disks.
If you have chosen to customize the Boot Camp configuration, you should define one or more (up to total 4 disk drives) custom Boot Camp disks. To do that, just replace an existing definition of the virtual disk by the custom Boot Camp disk definition. A custom Boot Camp disk may include several partitions from the same hard disk.
Parallels Boot Camp supports disks with GPT or MBR disk partitioning schemes, but handles them differently.
Windows XP and Windows Vista are supported as bootable OSs on GPT disks.