USB devices not being seen in anaconda during RHEL4 kickstart

[Ben]

Wotcha,

I've got a pile of Sun x4140 and x4240 servers here which I'm required to 
install RHEL4 (update 7) on.  I've already installed RHEL5.3 on them 
flawlessly, booting from a USB stick with a syslinux and <machine>.cfg 
kickstart setup on it for a HTTP-based install.  The USB device appears as 
sdb.

This works (for installing RHEL5.3 Server 32-bit):
label wibbly
   kernel vmli5s32
   append initrd=int5s32.img ks=hd:sdb1:/configs/wibbly.cfg console=ttyS0,9600

This does not (for installing RHEL4 u7 AS 32-bit):
label gonk
   kernel vmli4s32
   append initrd=int4s32.img ks=hd:sdb1:/configs/gonk.cfg console=ttyS0,9600

Now I'm trying it with RHEL4 and failing utterly.  The machine itself will 
boot from the USB stick in the proper manner via syslinux and display the 
boot.msg.  It'll accept keyboard input and boot the vmlinuz and initrd.img 
for AS4 (update 7) and start the process (see above).  However at the point 
at which it should read from 'sdb1' to get the configuration (the IP, HTTP 
kickstart tree URL, etc.) it just presents me with the dialogue box for 
selecting the language to install in.  Not only that but if I proceed 
manually and get to the partitioning stage there's no sign of anything but 
the internal (RAID) disk(s) (announced as sda).

I've tried disabling the "Hand-off EHCI" setting and trying all the other 
USB-related options in the BIOS but nothing seems to make anaconda see USB 
devices.

Does anyone have any suggestions, please?

With thanks,

Ben
-- 
Unix Support, MISD, University of Cambridge, England
Plugger of wire, typer of keyboard, imparter of Clue
         Life Is Short.          It's All Good.