I have same problem to translate "Bank wire" to my language (Thai). Now I found how to translate it.
1. Make directory "Bankwire" /theme/default/modules/
2. Copy .tpl to "bankwire" directory. They're in /modules/bankwire/ please looking for them in sub directory.
- payment.tpl
- payment_execution.tpl
- payment_return.tpl
and make file YourLang.php for example (th.php for Thai language) => chmod 777
3.Go to BackOffice /localization/translate select "installed modules translation" then click your flag you want to translate
sorry about my bad english.