Alpha Brush Will Not Accept Texture

Yes, so I dropped in a grayscale 512x512 texture from World Machine, and attempted to fit the Alpha Brush with it, but it would not work. How so? Have I not done something? Is this a bug?

I am having a similar problem. Did you ever find a solution?

For anyone still wondering:
The texture needs to be 8bit.
Here is a working example texture you can examine in case I missed something.

Can you elaborate a bit more. I have a lot of texture brushes. Yours when I got to properties and details it shows 24 bit. I cannot understand whats wrong. I just cant import them. I have some that work but others arent working. Can I talk to you anywhere?