How do I extend the xmlsitemap module to include the google news / images and videos formats

Question

The xmlsitemap module covers the standard google xml site map. However, https://support.google.com/webmasters/answer/178636?hl=en is the information for the google image search and the specific markup for creating a sitemap for image content. Likewise https://support.google.com/webmasters/answer/80472?hl=en is for video content. I don't think that the xmlsitemap module supports these additional types. (Google news sitemap is another one). Can anyone offer any more information about extending the module or if there are any patches that will achieve the above.