How does the "patch" in VMT work ?

[surreal shard]

I was trying to make my life easier by including a patch file that would add stuff to the main vmt but it rather overrides basecolor instead

[proper cedar]

You use insert like this

{
    include materials/models/combine_soldier/combinesoldiersheet.vmt
    insert
    {    
        "$basetexture"     "Models/Combine_soldier/Combine_elite"
        "$bumpmap" "models/combine_soldier/combine_elite_normal"
        "$selfillumtint" "[2 0 0]"
        "$phongexponenttexture" "models/combine_soldier/combine_elite_phong"
    }
}