solution: pass extra hdc=ide-scsi argument.
hdc=ide-scsi does not work, see this thread: http://forums.gentoo.org/viewtopic.php?p=1127379 concerning this bug.
There is supposedly a kernel argument that will enable the media bay, and this was supposedly a bug in 1.4 as well.
The same issue occurred here: http://bugs.gentoo.org/show_bug.cgi?id=6269
I'm guessing that CONFIG_PMAC_PBOOK isn't set in the ISO kernel config, same problem as last time. Any chance of getting a new ISO up?
Closing, this bug is pretty much irrelevant after more then 1 year. Please,
reopen if this issue still exists with current ppc release.