Curved railing

How do I get this to work? I have placed the curved decking outside and also on a second floor balcony but when I try to put fencing it just goes diagonal and not curved. I wish there was a build mode info list if how to do all the things in build mode like this.

I'm trying to picture this and I've yet to finish my first cup of tea so I'm sorry if I get it wrong. I think what is happening is you are placing the deck without the fence. There is an option to place a deck with fence that is curved. You can change the style of fence easily but I think for whatever reason they made it so you can't "draw" your own fence line and curve it. The deck with curved fence is right next to the curved deck in the build options.

If I got it right, yippie and I hope I helped! If I got it wrong, I blame the early hour and lack of caffeine!