[c-nsp] Two Cisco 8xx, point to point multicast??

[Neal Rauhauser]

   I have a friend who has been gifted with two new Cisco 881s and strict
orders to get multicast flowing between two locations using a GRE tunnel.
We're happy with our IP routing, tunnel protection won't be a problem, but
it's been forever since I touched multicast and these things show no signs
of PIM or IGMP. Are we trying to teach a pair of pigs to fly here, or does
someone have an example config for how to do this with a consumer edge
device like this?

  We've got one application, so the group & UDP port will be known.