InvoiceFile InvoiceID in WSDL shows as type String
Known Issue: InvoiceFile InvoiceId field shows <element minOccurs="0" name="InvoiceId" nillable="true" type="string" /> while our Knowledge Center indicates its Type: zns:ID
Reference Number: BIL-18222
Status: defect on our end that will be fix on our January 2016 release. Please note that version 74.0 will have correct type which will be Type: zns:ID and we cannot change previous version WSDL for backward compatibility.