I'm trying to customize the login pages for the dev portal and publisher and I'm referring to the below documentation.
The 1st step tells to download the Identity Server and in the 2nd step, it says to start up the server using api-manager.sh which could be a mistake.
However, I have the following questions related to the scenario.
I guess the documentation should be updated. You can use the existing jsp files in the authentication endpoint if you use OAuth2/OpenID. If you are using SAML, then you have to use WSO2 IS as the IDP with WSO2 API Manager.
Some samples can be found in [1].
By default API Manager uses OAuth2/OpenID. You can do the service provider configurations in API Manager. OAuth2/OpenID and SAML use the jsp files used in the authentication endpoint.
[1] - https://github.com/wso2/samples-is/tree/master/re-branding-the-default-login-page