what is Authorization: < Standard OAuth credentials > ? and how can I send it by a post method in C# ?
I do have the OAuth access token which is a string as such
oauth_token=A%3Dvh....aRg--&oauth_token_secret=bd46a....c9239&oauth_expires_in=3600&oauth_session_handle=ALtT.....3J1N4Zg--&oauth_authorization_expires_in=784964948&xoauth_yahoo_guid=TUSKED5...NCIA
This particular guide may assist you, he goes into great detail and explains each process with a lot of detail. The details are to use it with sites such as:
But it goes into detail of utilizing the token you receive and physically linking your application so your properly utilizing those OAuth Request.
I'm not sure if I misunderstood you and you aren't using such an API, if you can clarify I'd be happy to try and assist you.