SSO fails between Federation and WebGate protected resources (on-premise)

OAM/OIF has been configured as IdP with wsfed for a cloud-based resource. We have other apps on-premise that are protected by a Resource WebGate and authenticated in a DCC WebGate. When we request a resource protected by the Webgate and then we move to the federation app, sso fails.

The configuration of scheme authentication is shared between the resources:

Challenge Redirect URL: https://sso.mydomain.com

Authentication Module: myLDAPScheme

Challenge URL: /oamsso-bin/login.pl

Context Type: external

But each resource has its own Application Domain:

Federation APP: IAM Suite (by default)

WebLogic APPs: CorporateApps (asociated to the Resource WebGate)