If you can't see either device, my first thought is that the IDE cable is not securely plugged into the board, the pins are off, etc. Something with basic connectivity of the devices sounds astray. Maybe you missed a row of pins plugging in the hard drive?

With iBooks, you always want to test everything before putting the topcase back on. It's possible to plug in audio, power button, and the trackpad without actually locking in and fastening the topcase down. This way, you can test everything and make sure it works before putting it back together. If you put together before you test, and something doesn't work, then you've wasted 20 minutes putting it back together, plus another 20 to get it apart again, etc. I've wasted many days of my life opening up a problematic iBook YET AGAIN. :-(

Good luck!