This is very, very late, but what the hell.
Set up a shortcut to cityofheroes.exe in your client_demos folder.
Right click it, and change the properties to something like
H:\Games\CoH\Clients\CohBeta\cityofheroes.exe -demoplay RWZ.cohdemo -demofps 30 -demodump -disable2d
You'll need to point the path to your CoH executable location, change the name of the .cohdemo file to the one you want to dump, and make damn sure you've got a lot of HDD space, because it'll get big, fast.