For report account.invoice use the following term:

[[ l.product_id and l.product_id.ean13 ]]

For account.invoice.layout of v6.0 this is more complex. You have to:

• Update file account_invoice_layout/report/report_account_invoice_layout.py and include a new field

  res['ean13'] = entry.product_id.ean13

• Update report and add

  [[ a['ean13'] ]]

I get this in my server logfile, but i believe it is not related to the ean term :

[2013-03-06 15:11:17,495][ravensara] WARNING:report:rml_except: " o.payment_ter$ Traceback (most recent call last): File "/opt/openerp/server/bin/report/render/rml2pdf/utils.py", line 90, in _c$ eval(n.get('rml_except'), {}, self.localcontext) File "/opt/openerp/server/bin/tools/safe_eval.py", line 284, in safe_eval return eval(test_expr(expr,_SAFE_OPCODES, mode=mode), globals_dict, locals_$ File "/opt/openerp/server/bin/tools/safe_eval.py", line 105, in test_expr code_obj = compile(expr, "", mode) File "<string>", line 1 o.payment_term and o.payment_term.name ]] : [[ (o.payment_term and o.payme$ ^ SyntaxError: invalid syntax