After watching your vid I think I could honestly say that you would have a hard time slicing up the map to get it into FPSC.
Mostly your models are square blocks with some compound boolean cut-outs using a single texture.
You would in fact find it much easier and quicker to create a completely new level using FPSC,even the stock media would be better.
You could also import some of the more elaborate parts of your models.
I dont want to be rude or anything but believe me you could build that map in a few hours and with more varied textures and more elaborate too.
You could also use your own photographed textures for realism if you want to base it on existing buildings.
If you wanted to recreate the map you have I think you would still get a lot out of FPSC,download the trial and give it a try and you will see what I mean.
best rolfy.