nvm, found it. My options are "ErP Ready", "Restore AC Power Loss", "Power On By PCI-E/PCI", and "Power On By RTC". ErP seems to be related to what I'm looking for, but it's disabled by default, and the info section at the bottom states that when ErP Ready is set to enabled, all other PME options will be switched off. After a bit more research, I'm convinced that my motherboard does not in fact support this feature.
