Just to add my two cents: I've used this hack to add a controllable glossy effect on some of my Vic4 skins, till I wrote a Python script to do this, and that's the moment when I understood that using a Python script, you can add and name a layer the way you want
Example useable in the Material Room, with the current material:

mat = poser.Scene().CurrentMaterial()
second_layer = mat.CreateLayer('Gloss')

you may even copy and past these two lines in Poser' Python Shell.

𝒫𝒽𝓎𝓁

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