Thanks, but… I have already tried this in the past, and the server will throw a 400-ish code everytime you try it, unless you contact an admin, and have him give you the okay to use this type of grant-flow in an application.
I think it was done that way to stop malicious application’s from getting people’s username / password.
EDIT:
Il give it a shot, you are doing it slightly differently than I did in the past.