Yes You can do this in Cubase 5.
Use the line tool. Point and click at the lowest point of an automation curve, drag to draw a straight horizontal line i.e. in 'Volume' automation lane, four automation points will appear automatically on the volume automation curve. and the track's Read Automation button will be automatically enabled. Actually, Cubase 5 has various automation curve shapes you can use, and more advanced features that allow you to see only certain types of automation data, or even suspend specific automation data if needed.
I have switched from LP9 to Cubase 5, and have been really having fun using Cubase 5, I find it much more intuitive, and logical to use than LP9, Cubase 5 has some unique features that are very useful, and not available in LP9 !