Creating a Hill/Slope

[arbones]

I am using Home Designer Architectural 2014. Working on a client's landscape plan. Using the software, I am trying to create a sloped area across the entire back of a backyard. The yard is flat for 30 feet back from the home. There is a short (30") block retaining wall across the yard at that point. The terrain is 30" high behind the wall, going back about 12". The slope begins from there, ending 10' from the original height of the flat area of the yard. I've tried using several options, but have been unable to create the hill. I also need to place a fence on terrain, which would be placed at the same height of the terrain. See attached picture. Sorry for the panoramic-style fisheye view of the picture. But hopefully you'll get the idea. Thank you!