I had the same problem, it takes a few days before you will see the VOD from Comcast, force a few call home on both your Mini and Roamio after about three days and all should work.
Originally Posted by gu014
I have a Roamio Pro - Xfinity on demand app is working just fine.
The Mini interface does not show the Xfinity app in the interface? Both devices have connected recently and are up to date.
My area (Philadelphia area) is listed as available for the Xfinity on demand on my tivos.
3 Roamio Plus upgraded to 2Tb & 3Tb, and 2 Minis,