if the driver on the 3.5 in floppy is called "DD-0"
and you do mount the floppy to "/tmp/ramfs"
from the instructions in post one
you have that gzip file
and extracted that file
dd if=hpahcisr-<version>.rhel5.x86_64.dd of=/dev/fd0 bs=1440k
and you HAVE put it on a 1.4 meg 3.5 in floppy
( using any old computer with a 3.5 in floppy that is built in -- as in an IDE drive )
if not a built in ide drive "/dev/fd0" will be where ever you mount it to
then install from the floppy
if the usb1 floppy is mounting during install to " /tmp/ramfs/DD-0"
You do know you can use a usb thumb drive or even a cd
instead of a old usb1 floppy drive
Have you contacted red hat tech support
this is a server install and you are paying a lot of cash for the required server license
you might want to use the support contract and ask them for help