Paint Shop Pro :: How To Apply Gradient Map To Brush

I was reading a tutorial on Photoshop about using a gradient map on a brush (the case in point was of drawing fire, with four colours, black, red yallow and white, making up the gradient map) such that you'd paint just once to get all four colours from each brush stroke. Here is an example. I was wondering how to do that in PSP X3 Ultimate. I am not new to PSP but I never used the more complicated brush features. Scripting doesn't scare me too much, if it comes to that, but I'd prefer a manual approach.