How do I add new search engines to Google Chrome's function of pressing tab to search a website?

I love this feature.

http://blog.xmlgadgets.com/google/search-any-website-from-google-chromes-address-bar-directly/

But I can’t get it to work with some websites because probably Chrome doesn’t detect it’s a search form.

E.g. Speckly: http://www.speckly.com/s/airport

I guess it would be detected if it was http://www.speckly.com/search.php?query=airport or something like that

Any way that you know to add it manually?

Thanks