Before you can use this feature you need to setup SAML 2.0 SSO on your WebLogic Domain. You can follow this blogpost for all the instructions. You can also do this with Web Services but then you need to follow this guide.
First we need to enable Generate Attributes on the Identity Provider Side.
Go to the myrealm security realm -> Providers -> Credentials Mapping -> your SAML 2.0 Credential Mapping Provider -> Provider Specific.
Also do this on the imported Service Provider Partner located at the Management tab of your SAML 2.0 Credential Mapping Provider. Open the Service Provider Partner and also enable here Generate Attributes.
Next step is to configure the SAML Service Provider.
Go to the myrealm security realm -> Providers -> Authentication -> your SAML 2.0 Identity Assertion Provider -> Management Tab.
Open your imported Identity Provider Partner configuration.
Now we need to add an extra WebLogic SAML Authentication Provider. This provider will process the virtual user SAML token with all its attributes and roles.