Thanks for responding. I need multiple taxes applied to the invoice. I have one tax in the tax item drop-down and the additional taxes as line items. I'm able to do this in Quickbooks following the instructions on this page: http://dataservices.intuit.com/support/articles/how13181
But if I create an invoice using the same instructions on Method or if I edit an invoice like that which was synched from Quickbooks, I get the error when Method tries to push it back to Quickbooks.