public Token getAccessToken(final Token requestToken, final Verifier verifier) {
this.config.log("obtaining access token from " + this.api.getAccessTokenEndpoint());
final ProxyOAuthRequest request = new ProxyOAuthRequest(this.api.getAccessTokenVerb(),
this.api.getAccessTokenEndpoint(), this.connectTimeout,
this.readTimeout, this.proxyHost, this.proxyPort);
request.addOAuthParameter(OAuthConstants.TOKEN, requestToken.getToken());
request.addOAuthParameter(OAuthConstants.VERIFIER, verifier.getValue());
this.config.log("setting token to: " + requestToken + " and verifier to: " + verifier);
addOAuthParams(request, requestToken);
appendSignature(request);