import existing wp blog to wpms new installation

hi,
i've a wp installation sub.domain.tld, now i want to include this in another wpms installation in domain.tld (the same)

there is a path to follow to import users without losing thinks?

i've WP 3.1.2 with BuddyPress 1.2.8, wp-fb-autoconnect, and some other plugin.

the problem is how to export/import users to old site in the new with the same table and possibility to login with fb?

dump wp_users & wp_usermeta change apparently the site to WPMS -> WP.

thanks for the help