I need to translate all messages in models.py, file located outside addons folder!!

I've been looking for translations of messages from this  specific file, but I realize that these messages are not include in any generated .po, I can't find it anywhere.

I'm missing something? What should I do besides overwrite this file and put all messages in other language.

Once again, I'm talking about the file located outside addons folder!!

Thanks in advanced.

Regards