I want to call an secured external web service from salesforce. I dont want to pass user name and password as part of my webservice call out since I dont want to maintain them in salesforce. This is basically enabling SSO. I tried making my webapp saml complaint. But login html from IDP is returned as webservice response to salesforce. I read about Secure Token Service (SAML Token Profile)? Is this the only way to call the protected external webservice using SSO? If so, how do i get security token from IDP inside salesforce after configuring SSO? If so i can send it as part of webservice callout to my protected webservice and my app can send the token to STS for validation. Any help is appreciated.