Find disk shelf serial number?

If your LogicModules, particularly the PropertySources and DataSources, are all up to date and it's not getting discovered, it just means that there's no out of the box LogicModule that discovers it. However, you've already answered the most difficult part of building this into LM: how to get the data. Can you access the HP SSA CLI through SSH? If so, you could write a simple Expect PropertySource to pull in this information. It sounds like this may be an instance level property, as opposed to a device level property, so you may need to look at the discovery of those instances and add a portion that discovers the serial number as an instance level property.