[CentOS] CentOS LiveCD on USB

I have been following these instructions:
https://www.centos.org/forums/viewtopic.php?t=501
to put a bunch of utilities (Clonezilla, SystemRescue, CentOS netinstall/rescue, etc.)
on a single USB key.  It works great for everything (including Ubuntu Live) except the
CentOS 6.4 LiveCD. (You can see my postings at the bottom of the forum.) When
booting the LiveCD, I got:
	Kernel panic - not syncing: Attempted to kill init!
	Pid: 1, comm: init Not tainted 2.6.32-358.el6.i686 #1
After removing "quiet" and adding "selinux=disabled", I got more information; the boot
stalls after finding devices, and gives:
	No root device "block:/dev/mapper/live-rw" found
dracut suggests adding "rdshell", which I did.  This was not helpful (I had no idea what
to do in the dracut shell), but did notice that in the dracut shell /dev/ did NOT seem to
contain my USB drive at /dev/sdb as I would expect. (One reason it seemeed not
helpful) So:
1) I used VFAT rather than ext2/3/4. Do I have to use ext2/3/4?
2) Do I need to rebuild the initramfs file somewhere in the CentOS LiveCD directory?
3) Is this just a straight-up hardware incompatibility? The computer is a brand-new
SuperMicro X10SAE Haswell system.

Thanks,
-G.
--
Glenn Eychaner (geychaner at lco.cl)
Telescope Systems Programmer, Las Campanas Observatory