The way I always accomplished this in DMB2 was creating a Descent 1 level, spawning the reactor, then converting it to a Descent 2 level. It kept the reactor but was a pain if you already had a level and did not want to redo it. I would imagine that this issue was solved by now as that was over a ...

I actually have a copy of DesEdit from the guy who created it some time in 2005. It's not a full level creation tool from what I remember, but rather can create specialized geometric structures (such as domes and spheres) for import. I'm amazed the functionality was not merged into a new tool ...