Does anyone know how RMS HQ assigns HQIDs and StoreID/IDs to items in the customer table?

We're trying to insert customers into the table programmatically, but HQ will assign its own value for the HQID, and I can't figure out where it gets its IDs from.  If we insert an item with the next consecutive value, HQ will also use that value if the user adds a new customer, causing a duplicate HQ.  If we use a HQID that is nowhere near what RMS is using, it will overwrite the HQID to some other value if the user edits the record, which could cause duplicates at the stores.

Any ideas?