Airport Design Question

I asked for a program the other day that I could use to creat my own airports and you guys told me AFCAD. Well I got it and have created and updated 3 airports so far, works great and easy to use, Thanks again guys. One more question on it though, can you use afcad to make the grassy areas around the airports? I have not seen any instructions on that in the manual. Or is there another program for that?