I have a series of utilities to generate Google sitemaps for my whole site.  These files are massive, and slow to build.  We want to start telling Google these pages are mobile-crawl-able too, by adding them to mobile sitemaps, but the documentation is unclear if I need to specify physically different files for my mobile URLs than for my normal ones.If this is my current sitemap:<?xml version=1.0 encoding=UTF-8 ?> <urlset xmlns=http://www.sitemaps.org/schemas/sitemap/0.9>    <url>        <loc>http://mobile.example.com/article100.html</loc>    </url></urlset>Can I simply change it to:<?xml version=1.0 encoding=UTF-8 ?> <urlset xmlns=http://www.sitemaps.org/schemas/sitemap/0.9  xmlns:mobile=http://www.google.com/schemas/sitemap-mobile/1.0>    <url>        <loc>http://mobile.example.com/article100.html</loc>        <mobile:mobile/>    </url></urlset>Or do I need to create new files with the additional markup, alongside my existing files?
Updating Google sitemap for mobile
google;sitemap;mobile