From Xojo Documentation
Inserts NewValue identified by Label. Used to insert multi-value properties such as phone numbers, email addresses, physical addresses, and so forth. The label should be any of these constants (or literals) defined on AddressBookData: LabelHome="Home" LabelWork="Work" LabelHomeFax="Home Fax" LabelWorkFax="Work Fax" LabelOther="Other" LabelPager="Pager" LabelMain="Main" For anything other than phone numbers, the only valid labels are LabelHome, LabelWork, and LabelOther. Passing anything else will raise a RuntimeException. The Message property of the exception will explain the valid labels. If the property being assigned a value is a custom property or a property the REAL Studio AddressBook implementation does not know about, it will pass in the label given and not manipulate it in any way.