there is a way to change it, I did it on my firefox profile, I just need to remember how... will post back.
Ok I have it
* In the address bar, type about:config (accept any warning)
* In the filter search field, type 'keyword.URL' (without the quotes)
* Revert the value to default, it should be 'http://www.google.com/search?ie=UTF-8&oe=UTF-8&sourceid=navclient&gfns=1&q=', if not, copy the value I posted in the field
* Restart firefox
And Voila!