I'm not sure what slogan you are talking about. If you have a link to the site, I can check it out but the calendar pagetype doesn't add any slogans. You will want to check the view.php of your theme, most likely. That is where page_types from an add-on will actually get rendered. The view.php has a line like '<?php print $innercontent ?>, and that will "spit out" everything an add-on's page type generates.

So any additional content should be in your theme's view.php.