The Address Book (AKA: Non-employee Lookup) is where contacts NOT loaded (i.e.: coming from) CMS-HR are maintained: in other words, folks who aren't and won't ever be in CMS-HR including Sponsor Contacts.
If the contact you're looking for isn't listed (isn't available) in Kuali, select "Generic Sponsor Contact" (aka: Address Book ID: 100295, First+Last Names: Generic) and request the contact addition using the following forms: