I wouldent use realflow at all for this, complete overkill and most of the job is in the shader rarther than the actual simulation. As a "close to" simulation will do considering that its going to be composited and that you can change the look of the simulation via bias settings and transprancy maps.

To be honest theres loads of ways to do this, particles and fluids combined would be my way, make a fluid simulation for the main smoke, with a ramp attached to the incandesence to control the look, with a mess about with the opacity and the imput bias for the incandessence it should look pretty good, and then use particles for the others.

As I say theres no singe shot solution for this, what I would suggest is digital tutors fluids kit and mayve the gnomon pyrotechnics dvd (not seen it myself so couldent comment).

Ohh also have a look into overburn, a great little free plug in that might give you some ideas if you reverse engineer them