How to make a new PLT?

I know how to edit existing PLT files, I did that long time ago for CPP - adding tintable lips and eyes, but I am struggling with making brand new plt for open face helmet.

I have the image in TGA format, but plt editor wants BMP, yet if I convert the TGA (with alpha background) into bmp and load it into PLT editor despite it looks same as other custom helmets (white background), once I try it in game the background is not transparent (as it is for other custom helmets) but yellowing-white.

Any idea what I am doing wrong? Or maybe I am using wrong editor?

Try this tutorial I wrote; always worth looking at the wiki!

As for transparency it should be entirely white pixels on the skin layer in my experience.

Hmm that is too complicated for me. I solved this by using this approach instead - Custom helm baseitem proof of concept | The Neverwinter Vault

this way I can use tga as an icon for new custom helmets and since I am hiding them at equip it doesn’t matter that the model is silver basic helmet