I attempted a hdiso install of Fedora 9 Alpha for i386. Booted the machine from
the Rescue image. The CD isos were on a (vfat-formatted) USB drive. 

Told loader to fetch images from sdb1, in the directory 9-Alpha/Fedora/i386/iso
and it happily loaded stage2 and continued into the GUI. anaconda.log has the
following message:

19:49:11 INFO    : Found hd stage2, copying /tmp/loopimage///images/stage2.img
in RAM as stage2

So the installer *did* find sdb1 and mounted disc1 just fine.

I did the normal steps - choose timezone, partition drive, etc. When it tried to
get repo metadata, the installer popped up a message like:

"Unable to read package metadata. ... Cannot retrieve repository metadata
(repomd.xml) for repository: anaconda-FedoraBase-$(datestamp).i386. Please
verify its path and try again. [Abort]"

Checked tty2 - /dev/sdb1 was not mounted, and neither were any of the ISO images.

I'm attaching the anaconda.log from that system.