Accessing Import ID for related records in Query

I'm using the Query API to retrieve information from the Receivables module about Clients Automatic Payment configuration. I would like to use this information to Import changes to the Default Amount field. I've tested the import proceedure and it is working. To accomplish the import I need access to the Import ID of the Automatic Payment record related to the Client via Query. I can obtain the Client Import ID via query, but I cannot locate the Import ID for Automatic Payment (or any other related records) in Query. How can this field be made available?