Please open file comment-wrapper.tpl.php to modify code to show content for portfolio content type. Now, we only restrict comment for Article and Product content types.
Ex: change <?php if($node->type =="article") :?> to <?php if($node->type =="article" && $node->type =="YOURCONTENTYPE") :?>
Thanks,
and = && does not work for me, use or = ||
Sudo= if content type is "this" or "this"
<?php if($node->type =="article" || $node->type =="YOURCONTENTYPE") :?>
;)