Problem Statement:
With the New Universal Login, I can include a screen_hint=signup parameter in the /authorize request to have the Universal Login page load on the sign up screen. When Auth0 is the acting as the IdP in SAML flows, the same screen_hint parameter is not automatically going to the sign up screen when the Universal Login page loads.
Cause:
While our docs state that the screen_hint=signup parameter is supported in requests to the /authorize endpoint, the same is not true for the /samlp endpoint that is used when Auth0 is the IdP.
Solution:
While this is not supported at the moment we do have a backlog item in to potentially address it.