Sword Deposit plugin not setting Issued Date

Good afternoon. I’m managing a OJS 3.1.2 installation, and i have been asked to backup our archive into an institutional DSpace installation. For this i have been using the SWORD export plugin. It works pretty well, but it doesn’t set the Issue publish date as date issued (dc.date.issued). Is there any way to add that to the deposit file? I tried editing the plugin files to achieve this, analog to the way other metadata is set:

In OJSSwordDeposit.inc.php at line 91:

$issue_date = $this->_issue->getDatePublished();
$issue_date = str_replace(' 00:00:00', '', $issue_date);
if ($issue_date !== null) $this->_package->setDateIssued($issue_date);

And in packager_mets_swap.php added to function writeDmdSec():

if (isset($this->sac_dateissued)) {

And in general:

public $sac_dateissued;

function setDateIssued($sac_thedta) {
$this->sac_dateissued = $sac_thedta;

But to no avail. Is there any way to make the plugin export published date as metadata?