Alright, good news is I am no longuer seeing the “The ID in the Client-Id header must match the client ID in the access token.” error.
The bad news is that even after implementing your changes and using a user token, I still get the “The value specified in the method field is not valid” error.
Just to be sure, when refering to “user token”, we are refering to the “access_token” fragment parameter sent to the callback url, correct?