pubDate in EML points to the 'true' entity publication date -- in EML we need that of the form

[isangil]

But we really need the publication date chosen in the data set field.

Instead of using $variables['pubDate'] = format_date($entity->created, 'eml_yeardate');
We would render the pubdate in the field "field_publication_date".

[jlaundre]

Instead of modifying eml.module I think it may be clearer to change template eml--node--data-set.tpl.php
From: <pubDate><?php print $pubDate; ?></pubDate>
to:
<pubDate><?php print format_date(strtotime($content['field_publication_date']['#items'][0]['value']), 'custom', 'Y'); ?> </pubDate>

The field_publication_date also has to be enabled in the eml display. I did it as plain and it works.

Jim