(Note: I have received permission to quote posts in public forums from MS people)
This was the answer given by a MS support person in a public forum.
In order to enable MSS features for WSS 3.0 users without involvement of new urls do the following:
- Go to Central Admin > Application Management > Manage Web Application Features (under web application management)
- Select your web application.
- Click on buttons to activate MSS search services for your web application:
Activate – Office Server Enterprise Search
Activate – Office Server Site Search
Now when you go back to your site,
Site Actions > Site Settings
will show you more options like search settings, scopes, best bets etc.
You can now Stop Windows SharePoint Services Search and verify that search on all sites continue to work.