ARR in place of TMG 2010 (Kerberos Constrained Delegation)

Asking this here as I figured TMG people may have the knowledge as well... 

Trying to replace TMG with ARR and use Kerberos Constrained Delegation. 

TMG is working properly to a backend server (app-01 for example).  TMG is using the SPN of app-01.domain.com and trusted for delegation in AD to http/app-01 and http/app-01.domain.com

Now, I am trying to set up ARR to do the same thing.  ARR is trusted for delegation with the same settings as above.  However, it is not working.  I am not sure how to set the SPN for the ARR server like I did in the TMG UI. 

Any thoughts? 
Mark