stardaug on "[Plugin: WordPress SEO by Yoast] Google doesn't see sitemap"

Yoast SEO: ver 1.4.3
WP: 3.5.1

Google webmaster tools indicates I do not have a sitemap.xml

I have Yoast SEO sitemap ENABLED

I DO NOT see in root dir of website post-sitemap.xml, catagory-sitemap.xml. Do not show up in any dir.

Any ideas what is wrong? and should the sitemap not be named "sitemap.xml" for Google to see it properly?

Suggestions?

Thanks.

http://wordpress.org/extend/plugins/wordpress-seo/