Passing HTTP session to next action

I start my (service) test flow with an HTTP Request in order to fill in username password to login to a restricted enviroment for my service test calls. Login works as desired, however the subsequent service test call starts a brand-new HTTP session which is not logged in causing the service test call to fail (response is user name / password form). How do I pass the HTTP session to the service test. Property connection type of the HTTP Request is set to Keep-Alive. Is there any way to pass the already logged in session to the service call step?