Lightmapper with custom shader Emission Map

I know that we can bake the Emissive map of a shader using the _EmissionLM Variable. in the shader code, the variable:

_EmissionLM ("Emission (Lightmapper)", Float) = 0

does nothing, but the Beast lightmapper recognises it anyway. When I build my custom shader the same way, I can’t get any emission on the lightmap. What am I missing?

got it, I had to name my emission map
_Illum (“Illumin”, 2D) = “white” {}
and I had to put Self-Illumin/ in the name of my shader.