Change language - almost done - but a small question

Hi.
I have webiste in Norwegian, an I have change some language-strings with no problems.
But I can't manage how to change the text "EXPIRE" in the dashboard.

The code in the default.php in like this:
<?php echo $this->html('subscription.status', $subscription, array('postfix' => '(' . $subscription->getExpirationDate()->format(JText::_('DATE_FORMAT_LC3')) . ')')); ?>

And I have figured out that the code subscription.status echoes the text "EXPIRE". But how to change that. Normal I look up a text string like COM_PP_INVOICES in nb_NO.com_payplan.ini and chang adjust the text to Norwegian. But which method shall I use here?

Regards
Ketil