So is the .htaccess file in this plugin wrong? I just installed it and I can see the sitemaps have been created in my /data folder, but I noticed the instructions/options page states:
By default the vBSEO Sitemap files will be located in your forum root. Use this field to specify a different location, for example, your site root: http://www.yourdomain.com
This isn't true though. Also, I think there must be something wrong with the .htaccess file that they provide you, because Google Webmaster Tools gives a 404 error as it's trying to access the forum root.
What file exactly are you meant to submit in to the Sitemap box on Google Webmaster tools?