Google submission and site map


I need to submit the website to google,google base and yahoo.The domain is compose of two sites.Joomla(works as a portal and CS cart as ecommerce solution)

Joomla is the home page( and CS cart is installed in the folder"shop"(

I know that cs cart generates itself a sitemap(wich can be used to google) and i have xmap plugin for joomla that generates sitemap.

The question is:i would like to send to Google and others one unique sitemap from the domain,but i do not know how to integrate both site maps(or if there’s another solution).Any help?:smiley: