Newsletter for Custom Categories (on Custom Post Types)?

Hello – I’m setting up an ecommerce site (using Woocommerce). Products in the catalog are defined using a custom post types (“product”) and there are a variety of custom “product categories” defined for the product custom post type.

My objective is, I’d like to send out a newsletter that includes the most recent “products” from specific “product categories”. I’d like to be able to select those product categories in the newsletter options when I create the newsletter.

I figured out how to include custom post types as a selectable option when defining a newsletter (e.g.: <?php $controls->post_types(‘theme_post_types’); ?> in theme-options.php)

I can also include normal post categories as a selectable option when defining a newsletter (e.g. <?php $controls->categories_group(‘theme_categories’); in theme-options.php?>

QUESTION: does anybody know how to also include CUSTOM categories as a selectable option(s) when defining a newsletter?

Thanks in advance.

http://wordpress.org/plugins/newsletter/