I wanted to post questions after a proper user authentication explained here. Is there anyway I can do this?
There isn't anything special in the API that would let you do this. You could send the user directly to the ask a question page.
I fiddled with the FireFox plugin I created to see if I could add the ability to post directly to the site to add an answer to a question or a comment if someone was already logged in. If I remember correctly there is some key that is required for the POST request and it wasn't obvious how that key was generated.
I already tried this. Complete exasperation with sending POST requests to StackOverflow - Meta Stack Exchange. So it's v2.0 or nothing.