T3_bs3_blank nav justified...

I need to make the mainmenu (not megamenu) justified using bootstrap 3 like in http://getbootstrap.com/examples/justified-nav/

In Bootstap 3 docs its documented as:

nav nav-tabs nav-justified

or

nav nav-pills nav-justified

I know that I must customize mainnav.php inside tpl/blocks but in the getbootstrap web the examples don´t use and ID like your mainnav.php.
So I am a bit confused. Must I remove id="t3-mainnav" and t3-mainav from class, too?
Any help about what must I write in the nav container of mainnav.php ?

Best regards to everybody and hope you can help me