How Can i make my ''sitemap_index.xml.gz'' like this site?

I couldn't find how to make my sitemapindex like this one:

http://www.turkforumuz.biz/sitemap_index.xml.gz

Plz inform me how to?

Hi Kadir,

Please install vBSEO Google/Yahoo Sitemap Generator v.2.0 - vBulletin.org Forum in order to achieve such sitemaps.

i've already installed vbseo sitemap builder.i want to how can i make my sitemap index like that one-->> http://www.turkforumuz.biz/sitemap_index.xml.gz

there is 85 sitemap file according to this index.But in my site i have only one index.i want to have like this

Increase your content...

each site map should hold 20,000 URLs or less.
after that, sitemap_x gets created for the next 20k.