I'm not familiar with Cassie's tutorial, but I just fooled around with your photos for a few minutes and got this:
It wasn't an elegant method, and I'm sure there are better ways of attacking it. However, what I did was: Take the original photo and convert to B&w, sliding the color adjustment levels for yellow, green, cyan almost all the way to white. I then superimposed that b&w photo on top of your adjustment coverted photo and played with the opacity levels to get the following. As I said, it isn't elegant, and it may not be what you want, but it may be a starting place. Hope that helps.
Software PS CS6
Platform Mac (Naturally)
Camera Canon 60D