not sure exactly what didnt work for you, but if you hit the search icon and then the mic icon and say your destination, it works like a charm
the reason that I know that you are searching in google maps is that beside the search field/box is a picture of the google map icon.
after you speak your destination or searched destination, simply select the pop-up balloon and then select navigate.
is there a one touch voice search? no. This is a two step process.
with your method, its a 3 step.
As for people on this site getting stuff wrong, we are all human, it happens. However, in this case, i can proudly state that I was not... i just maybe didnt explain it well enough.
Actually maybe I just found what you meant...
Did you mean, instead of touching the search button, to hit the menu button and choose search from there? That gives me a microphone option, oddly enough, although it's more clicks: 1: menu button, 2: search button, 3: "back" to get rid of the soft keyboard, 4: microphone button.