With spring-cloud Angel.SR3 release I followed example in https://github.com/spring-cloud-samples/sso and things work fine with spring-boot 1.2.6.RELEASE.
However with
You just have to use org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter
and carefully use this annotation org.springframework.boot.autoconfigure.security.oauth2.client.EnableOAuth2Sso
I've written carefully because its behaviour depends on where you add it. As stated in the javadoc:
Enable OAuth2 Single Sign On (SSO). If there is an existing WebSecurityConfigurerAdapter provided by the user and annotated with @EnableOAuth2Sso, it is enhanced by adding an authentication filter and an authentication entry point. If the user only has @EnableOAuth2Sso but not on a WebSecurityConfigurerAdapter then one is added with all paths secured and with an order that puts it ahead of the default HTTP Basic security chain in Spring Boot.
Hope that helps!