[Freeswitch-users] session.originate requires existing call leg?

I am attempting to programatically call out from FreeSWITCH to my office phone as a test and simply play some music using Javascript. session.originate() looks closest but the first argument is an existing session (A-leg). But what if I'm creating the A-leg of the call? Do I just: session = new Session(); session.originate(session, my_destination); ? Or does 'session' exist even though there are no channels connected and if so can it act as the A-leg? Thanks, James