I am trying to boot FC5 (same result form CentOS DVD) from a USB DVD drive. The DVD is good because I have used it to load other systems that have internal DVD drives and the system BIOS does support the boot from USB option.

The system boots off the external DVD and then launches into a menu that asks for my install source.
I get the following options:

Local CDROM
Hard Drive
NFS Image
FTP
HTTP

I have tried local CDROM but that picks the internal CDROM of the system, NOT the USB one.

I tried Hard drive and that give me a choice of /dev/hda /dev/hdc

I also tried to boot with the: linux askmethod parameter and no good.

How can I tell the installer to use the USB DVD it just booted from as the install source?