Network theme and search across network sites

Hi,
Just installed network theme as the opening domain (domain.com)
Have 3 further sites setup - (WP 3.1 multisite)

When I search within domain.com no content is returned.
The other 3 sites all have content, though are using custom post types.

What i get returned is:
Sorry, we can't find the search keyword you're looking for. Please try selecting a menu item from above or to the side of this message to get where you'd like to go.

Can you confirm the search is Network wide...or make any other suggestion.
Thanks