EBTax API to perform calculation prior to Payables Interface Import

Hi,  We have a requirement to invoke R12 Payables Interface Import with EBTax engine calculation turned on. However, it is required that invoices failing validation because of the tax calculation remain in the Payables Interface tables. Hence, I am thinking that there may be a way to call EBTax outside EBS and prior to the Import process is lunched. I am not sure if there are now R12 APIs to do so?
 I also would like to solicit your feedback on the best method to ask the Payables Import to reject these invoices so that they will show up in the Rejection Report.