Ordered + replaced new HD but it is not recognized

Followed the thorough and detailed iFixit instructions for replacing my hard drive using tools and a hard drive ordered from iFixit. Very straightforward. Afterwards, I started the computer from a bootable external drive, the computer works fine, but the hard disk utility does not see the drive. I got out my mac mini and started the powerbook in target mode - the firewire symbol appeared on the screen of the powerbook to let me know that it was indeed in target mode, but again, running disk utility on the mac mini did not see the new drive I installed in the powerbook. I'd like to exhaust diagnostic options before I have to go back and open it up again. Thoughts ?