Mix HttpBasic and FormLogin in Spring Security with Spring-boot-starter

I use spring-boot-starter 0.5.0.M6 with spring security to build my application which contains:

1. "/admin/"**: should be accessible to anyone have role ADMIN, form-based login
2. "/api/"**: should be accessible to anyone have role API, http basic login

My first attempt was:

@Override
protected void configure(HttpSecurity http) throws Exception {
      http
        .authorizeRequests()
          .antMatchers("/resources/**").permitAll()
          .antMatchers("/admin/**").hasRole("ADMIN")
        .and()
          .formLogin()
          .defaultSuccessUrl("/admin/home")
          .loginPage("/login")
          .permitAll()
        .and()
          .logout()
          .logoutRequestMatcher(new AntPathRequestMatcher("/logout", "GET"))
          .permitAll();  
      http
        .authorizeRequests()
          .antMatchers("/api/**").hasRole("API")
        .and()
          .httpBasic();
}

With this approach:

1. all the "/admin/" and "/api/" can authentication use both basic & form-based login. This is not a critical issue.
2. when any security issue occurred, eg: authentication failed, or authorization failed, the login form is shown. This is a critical issue, I want if /api/** get authentication failed or authorization failed, it show the basic authentication popup with 401/403 status code.

Then I try with the solution from https://github.com/spring-projects/spring-security-javaconfig/blob/master/samples-web.md#sample-multi-http-web-configuration, but I only able to secure either /api/** or /admin/** but not both, depends on which one I annotated with @Order.

Please give me a hand.

Thanks much