Howto test an API/Service which is secured by CAS - Server?

When the URL is accessed unauthorized, the browser is redirected to CAS-Login-Page, then back to the originating URL with an auth-ticket in url-parameter.
Can someone tell me how to use Postman for testing such URLS ?
thank you

update: partly success with a seperate request to the login-form of cas-server:

was fiddeling around with pre-request-script but eneded up doing a seperate Post-request with x-www-form-urlencoded body containing the fields: username, password, execution, eventId.

It authenticates, and from this point on, any request to the app is authenticated. Altough i have some issues when doing the same over a proxy …