Sitemap Updating with Custom Post Type

Hi: I am using this plugin on a mutli wp install for one website only. The site uses http://www.studiopress.com/plugins/agentpress-to display real estate listings. To use the plugin I created taxonomies and custom post types. This real estate listings are not appearing on the sitemap. Can you please help me with what ever special configuration is necessary to get these to auto update on the XML sitemap?

Here is a real estate listing created from the plugin:

http://stsimonsrealestatebuzz.com/listings/2920-sea-island-drive-sea-island-ga-31561/

And of course here is the XML sitemap:

http://stsimonsrealestatebuzz.com/sitemap.xml

I appreciate all help. Thanks.