RHEL5 installer not seeing second HDD after RHEL6 installation

Hi, all. I'm new to the groups and hoping someone can give me some help with a peculiar problem I'm encountering.

I've currently got a pair HDDs that were used to install RHEL6 on them. When I installed RHEL6, I set up the /boot partition on a software RAID1 device (/dev/md0). The rest of my system and swap are installed to software RAID 1 devices that are also configured as logical volumes. For reasons not worth going into, I am now required to install RHEL5 instead. When I boot up on the RHEL5 installation CD (#1) and it gets to the storage partitioning step, the installer is only seeing one of two HDDs (it found /dev/sda and not /dev/sdb). My guess at this point is that it's due to the installer reading the disks and finding the previous partitioning layout on it. How do I get the installer to see both HDDs again? I'd like to start from ground zero as it were.

If I have Disk Druid delete all of the found partitions on the discovered disk and create a default layout then go back to disk druid again, will it find the second HDD?

Thanks in advance!