RAID / USB Hang

[RqtballPro]

I have an external Firewire/USB hard drive and I found that I need to shut it down in order to reboot back to the desktop otherwise it just hangs at the RAID part of the POST.
This does not happen when I have the Firewire connection only on the USB.
I would rather use the USB connection, does anyone know why this is happening and how to fix it?
Thanks again for your time.

[Tansunn]

Does your BIOS allow booting from external USB devices? If so, does the USB device come before the hard drive in the boot order? That's the only thing I can think of that might cause this.