How to create a Child Customer Account using FBDI

Summary:

Need to load a customer account and bill-to, ship-to site records against an existing Parent party. Parent has already been created, with Party, Party sites, Account and Profile records created via FBDI upload. Now trying to add a Child account and sites. Tried various combinations in FBDI template (CustomerImportTemplate), I'm able to create the Child Account but the Bill-To and Ship-To sites for the child are not created.

Content (please ensure you mask any confidential information):

In CustomerImportTemplate populated data in the following tabs with the PARTYSITES and PARTSITESUSES using the Party Original System Reference for the Parent customer that was previously loaded via FBDI