How to enable Request and Response Logging in the .Net DevKit V2

How to enable logging for the XML?

I tried to follow the directions from http://docs.developer.intuit.com/0025_Intuit_Anywhere/0200_DevKits/0100_IPP_.NET_DevKit/0600_Logging

I put the code in a test program derived from the HelloIntuitAnywhere for a Transaction Add

So I put it under the normal setting in our InvoiceAdd procedure

realmId = HttpContext.Current.Session["realm"].ToString();
accessToken = HttpContext.Current.Session["accessToken"].ToString();
accessTokenSecret = HttpContext.Current.Session["accessTokenSecret"].ToString();
consumerKey = ConfigurationManager.AppSettings["consumerKey"].ToString(CultureInfo.InvariantCulture);
consumerSecret = ConfigurationManager.AppSettings["consumerSecret"].ToString(CultureInfo.InvariantCulture);
intuitServiceType = (IntuitServicesType)HttpContext.Current.Session["intuitServiceType"];
oauthValidator = new OAuthRequestValidator(accessToken, accessTokenSecret, consumerKey, consumerSecret);
context = new ServiceContext(oauthValidator, realmId, intuitServiceType);
commonService = new DataServices(context);

////////////////////////////////////////////
//OAuthRequestValidator
oauthValidator = new OAuthRequestValidator("<<accessToken>>",
    "<<accessTokenSecret>>",
    "<<consumerKey>>",
    "<<consumerSecret>>");

//ServiceContext 
context = new ServiceContext(oauthValidator, realmId, IntuitServicesType.QBO);

context.EnableServiceRequestsLogging = true;
context.ServiceRequestLoggingLocation = @"c:\IPPlogs";

//////////////////////////////////////////

But get InvalidTokenException on

context = new ServiceContext(oauthValidator, realmId, IntuitServicesType.QBO);