Jason:
It turns out that, no, the SATA-DOM isn't operating on pin 7 power and needs the power cable to run on the Supermicro motherboard.
Everyone:
By Jove, I did it! I used the iso of a cloning program called "Clonezilla" via IPMI's virtual media utility to copy the content of my old USB drive to my new SATA-DOM. Thanks to all for your help–in particular to Stephen.