Federation with OAuth endpoint in ADFS 2.0 for Windows server 2012 R2

Hi

I read Vittorio Bertocci posts about ADAL and ADFS 2.0 for Windows Server 2012 here and here. I also follows ADAL samples here. 

In all the above ADFS acts at an OAuth authorization server and provides the client application with a JWT token after the client authenticates using username and password credentials.

I would like to test a federation scenario. There are two ADFS servers with mutual trust. The client authenticates against one ADFS and receives a SAML token, then it request an OAuth token from the second ADFS server and authenticates using the SAML token it has.

In the OAuth specification there is no definition how users should authenticate before they can get the OAuth token, yet I have not seen any reference for different types of user credentials in ADAL API, I could find find any clue about a federation scenario in which client wish to authenticate using a SAML token.

Can anyone refer me to a sample or the relevant area in ADAL API that supports federation?

Thanks

Manu 

Manu