GetPostingURL is used to get the correct URL for a specific conference centers Live Meeting API processor.  This call should be made at the start of each API session.  Your conferences center's posting URL may change.  So the result of this call must not be hard coded in your application.  Also, long running applicitons should periodically refresh their posting URL.

The posting URL for a conference center can be retrieved using an https GET to the following URL. 

https://www.livemeeting.com/cc/<conference_center>/xml/4.0/GetPostingURLRequest

I have included a C# code sample that uses HttpWebRequest/Response to return the posting URL of a specific conference center.

Enjoy. And remember that this code is for informational purposes only, I make no warranties ... blah, blah, blah ... (don't sue me if it doesn't work).

public string GetPostingURLRequest(string confCenter){
    string strUrl = string.Empty;
    XmlDocument xmldoc = new XmlDocument();
    // Get the posting URL.
    getPostingUrl = String.Format(
        https://www.livemeeting.com/cc/{0}/xml/4.0/GetPostingURLRequest,
        confCenter);

    // Send the GetPostingURLRequest message to the conference center;
    HttpWebRequest myReq = (HttpWebRequest)WebRequest.Create(getPostingUrl);
    myReq.Method = "GET";
    HttpWebResponse myResp = null;

    try
    {
        // Get the response from the conference center
        myResp = (HttpWebResponse)myReq.GetResponse();
        Stream respStream = myResp.GetResponseStream();
        if (myResp.ContentType == "application/xml")
        {
            StreamReader reader = new StreamReader(
                                      respStream, Encoding.UTF8);
            xmldoc.Load(respStream);


            // Retrieve the url attribute of <GetPostingURLReply>
            XmlNode attrUrl = xmldoc.SelectSingleNode(
                    /PlaceWareConfCenter/GetPostingURLReply/@url);
            if (attrUrl != null)
                strUrl = attrUrl.Value;
        }
    }
    catch (Exception e)
    {
        // Log the error message or do other error handling routines.
        Console.WriteLine("Exception: {0}\nTrace: {1}", 
                                 e.Message, e.StackTrace);
    }
    finally
    {
       if (myResp != null)
          myResp.Close();
    }
    return strUrl;
}