Sitemaps and SEO wordpress MU Style plugin - Conflict with Google XML Sitemaps plugin

Hi All,
On one of my Wordpress MU installation I had installed "Google XML Sitemaps" ( http://wordpress.org/extend/plugins/google-sitemap-generator/). This plugin doesn't work on MU.

I just installed "Sitemaps and SEO wordpress MU Style plugin" without "All in SEO Plugin" and it didn't work.

The sitemap being generated is still from "Google XML Sitemaps" plugin even though it is deleted.

Seems very strange
1) Why the "Google XML Sitemaps" still being used when it is deleted?
2) Why "Sitemaps and SEO wordpress MU Style plugin" doesn't work?

Am I miss something?