Hello list.

I'm upgrading a 1.1 cassandra cluster to 1.2(.13).
I've read here and in other places that the best way to migrate to vnodes is to add a new DC, with the same amount of nodes, and run rebuild on each of them.
However, I'm faced with the fact that I'm using EC2MultiRegion snitch, which automagically creates the DC and RACK.

Any ideas how I can go about adding a new DC with this kind of setup? I need these new machines to be in the same EC2 Region as the current ones, so adding to a new Region is not an option.