<?php // don't include this in your functions.php

function si_set_default_terms_notes( SI_Invoice $invoice ) {
	$invoice->set_terms( SI_Invoices_Edit::get_default_terms() );
	$invoice->set_notes( SI_Invoices_Edit::get_default_notes() );
}
add_action( 'si_create_invoice_on_est_acceptance', 'si_set_default_terms_notes' );