Facebook Private Messaging - facebook

Question

It is said, that it is not possible to initiate new conversation through the API alone, except using Facebook's own Form integrated in the app. Is this correct, or is there some new API, which enables me to initiate a new conversation?
To reply to an existing conversation, I retrieved the conversations id using the following FQL Query "SELECT thread_id, . WHERE viewer_id={0} AND folder_id=0". Afterwards I retrieved the PageAccessToken for my app page using my user Access token, and tried to use this call:
*You can reply to a user's message by issuing an HTTP POST to /CONVERSATION_ID/messages with the following parameters [conversation id, message]. A conversation ID look like t_id.216477638451347.*
My POST Call looked like this (this is not a valid thread id): /t_id.2319203912/messages with message parameter filled. But it always said "Unknown method". Can you help me out with this one? Is there a parameter missing? I passed in the page's Access Token to call this one.
Is there some API out (except Facebook's Chat API), that I am missing, which can send private messages to users?
Edit:
What I wonder about is, that the code below only returns a single page, the application's page. Is this correct, or is there another page token required? This is what bugged me the most about the returned page.
The FacebookClient uses my UserToken to perform the next following task.
This is the code to retrieve my Page Access Token:
dynamic pageService = FacebookContext.FacebookClient.GetTaskAsync("/"+UserId+"/accounts").Result;
dynamic pageResult = pageService.data[0];
_pageId = pageResult["id"].ToString();
return pageResult["access_token"].ToString();
Now the code to retrieve my ConversationÍd:
dynamic parameters = new ExpandoObject();
parameters.q = string.Format("SELECT thread_id, folder_id, subject, recipients, updated_time, parent_message_id, parent_thread_id, message_count, snippet, snippet_author, object_id, unread, viewer_id FROM thread WHERE viewer_id={0} AND folder_id=0", FacebookContext.UserId);
dynamic conversations = FacebookContext.FacebookClient.GetTaskAsync("/fql",parameters).Result;
The following code is executed using the access token retrieved from the code above (page access token request).
Now the Code used to send the reply:
dynamic parameters = new ExpandoObject();
parameters.message = CurrentAnswer;
string taskString = "/t_id." + _conversationId + "/messages";
dynamic result = FacebookContext.FacebookClient.PostTaskAsync(taskString,parameters).Result;
return true;
I also tried it with facebook's graph API Debugger using the token, which is returned by my first part of code. But with the same error message.