Infernal Particle Emitter

Does anyone know how to change the color of fire around the infernal? I have seen this done many times and know that you have to convert the mdx to mdl then look for the section under "Segment Color", but I don't get how to define the color.emote_confused

just tint the unit, the fire changes also

No thats not what I meant, I want to change the color of the fire only. This is because I have other units like the undead mage I want to change.

should be part of the skin then