[keycloak-user] SAML2.0 Identity Provider modify authn context / extensions

Hi, Is there an easy way to add stuff to the authn context or add extensions to the AuthN request? Or even add query parameters to the destination url? Context: The SAML2.0 Provider I'm integrating with supports several auth methods. Usually you would end up on a method select page, where the options are presented to you, once you've been forwarded to the IDP. They do however support selecting an option directly by modifying the authncontext. They also support prefilling information by adding extensions to the authn request or adding supplying it through query params. Kind of like "login hint". So. Easy way, or do I have to extend SAMLIdentityProvider? Martin