Translation [#2437131]

The theme doesn't support internationalization for some of its templates: To enable it to translate "Posted on: ... - By: ...", I edited the node.tpl.php:

print t('Posted on:'); print $date;

print t('By:');

This helped me but there is yet another problem: the Date is not translated either. It's now in this format: 20 February 2015. If I select another theme the translations kicks in but not with multipurpose theme. Is there anything that can be done?