Does Siebel Support Form based authentication in OutboundWebService

Hi,

There is an external webservice hosted which is returning a HTML page on sending a request. The external team is suggesting to use Form based authentication method to pass credentials and use JsessionId that is sent in the HTTP header. Does Siebel support this feature? I tried using endpoint as Local and making 'SendReceive' call of 'EAI HTTP Transport Adapter' but not sure how to send the credentials ? Also how would I know if it is authentication page or actual response ? Should I be checking if the response has SOAP message etc.. is there any out of box