You could not be flattening the scraper enought in the first step. You should be able to feel quite some burr on it. Also what i do is not go directly to the 80 degree angle, but slowly get there you should put some what amout of force on this, enough to curve the scraper as you move the shank across. also before you try to sharpen it, make sure there is no burr on the edge already. Run it flat aginst a piece of sand paper to make sure its flat. Also when you cut with it you can get better cuts by bending the scraper, so it has some what of a rounded point, as you push it through the wood.
I use an attachment on my file when making the burr. Its just a long metal with a clamp that you put your file in and it makes a side with the 90 degree agle. they are fairly cheap.