hello ,
if someone have an idea .
i have change in this file account_print_invoice.py
path : addons/account/report/account_print_invoice.py
###
import time
from report import report_sxw
from tools.amount_to_text import amount_to_text_fr
class account_invoice(report_sxw.rml_parse):
    def __init__(self, cr, uid, name, context):
    super(account_invoice, self).__init__(cr, uid, name, context=context)
    self.localcontext.update({
       'time': time,
       'amount_to_text_fr':amount_to_text_fr,
###
then i add in the report invoice 
[[ amount_to_text_fr(o.amount_total,'Euro') ]]
with openoffice
but nothing appear when i print a new invoice
thks
 
                        
Is there any error message in the logfile? Did you update report "account.invoice"?