Preferences, Toolbars, Progress Bar. Shift click on the form submit button to open the second search engine new window. Or, right click and duplicate the window and perform the search from the second window. Please support the Opera user base by requesting they include this as an option in future releases. In 5.01, the Google searches now go direct to the search engine.
Search engines can change their search string values.
They also have strict usage agreements that prohibit automated or programmed queries. So a redirect service is used. Bfast maintains the urls, search strings, and has agreements for usage with all of the search engines listed. Don't we all, don't we all. You can still use just a single letter in an address bar to search.