Fill Layer at 0%.

I'm currently trying to work with this tutorial here: http://psdtuts.com/photo-effects-tutorials/photoshop-button-maker/

However, it's a bit poorly written with vague details, and I am stuck on step seven. It says:

Step 7:

So next we want to make the button interchangeable. To do that we simply get the main green layer and set the Fill to 0%

Fill is a bit like Opacity except that if you make something 0% Opacity then you make the layer styles transparent too, whereas if you make it 0% Fill, the layer styles are still visible. This is perfect for us because we get rid of the green, but still have everything we need to make our buttons. Now all we need to do is slot something underneath.

When I set the Fill to 0 percent, nothing happens. I even duplicated the green layer to make sure that it would go away at 0 percent, but no such luck.

I also don't think you can apply layer styles without having an existing layer, am I right? Because the point is to get rid of the green color but still have the layer styles there.

If anyone has suggestions, I'd appreciate it.

What about Layer Styles? Did you copy them from the Sample file or did you set them by yourself? If you did it by yourself, did you change option or just apply style without changing options? What blend mode and opacity is set on Gradient Overlay? I'm asking this because... if gradient overlay blend mode is normal and opacity at 100%... then changing the fill of the layer won't change anything...