-// echo "<input type='button' name='button' value='"._("Print this order")."' onclick=\"".
-// print_document_link($order_no, "", false)."\" class='inputsubmit' />\n";
+// button("button", _("Print this order"), print_document_link($order_no, "", false))";
+// or if a button inside a TD
+// button_cell("button", _("Print this order"), print_document_link($order_no, "", false))";
+//
+// You only need full parameter list for invoices/credit notes