Almost there. I'd use your base color art to specifically create a texture for the glow channel. the lighter the color, the more intense the glow. So, you may want to turn everything black except the glowing portion and brighten that up in your texture editor/painting program.

If you're interested, you already have an example in your browser that shipped with Carrara. Look under your shaders > Misc > and there is a shader called "Control Panel". It's the one that I used for my example. There are different textures for color, bump, shininess, highlight and Glow. After looking at that, you'll have an "aha" moment for sure.

Mark