A suggestion would be to check the jumper on the IDE hard drives if they are in the correct position. Usually IDE hard drives may have jumpers which allow you to set the hard drive either as primary or scondary.
i have done that.. The drives show up perfectly in bios drive configuration as master and slave..
Actually, I had a similar query long time ago, I had two drives, where each one has an OS on it. But when I connect both drives, it goes only on the first drive. I did not get any menu to choose which OS to boot.
Since I had Windows XP and Vista, I used a software called http://www.vistabootpro.org/ to have a dual menu.
May be you can give it a try.
to bad they don't have a trial version.. I don't mind buying it, but i would like to try it first..