Number251137

So, for those who want to know, it seems that there is a simple solution to this conundrum - Ctrl + R! Yes, apparently,the Hook 5 files don't load up if you select the Killbill texture, but they do if you refresh the screen! Then if you deselect the clothing item and then reselect it, the _norm & _spec files don't show up again.
Weird. But at least we now have a solution!

Okay, so _Hook5data is mostly used to store the following files:
Env maps
Particle effects 
Skins (_spec & _norm) 
 
 

https://www.loverslab.com/files/file/14540-simple-t**-encoderdecoder-batch-files/
https://www.loverslab.com/files/file/14547-tkshelltools/
There we go! 🙂
 

No problem. Yeah, you're right, but I guess no-one thought than someone would want to have a different colour arm! Lol
Okay, the next best thing would be to create a skin layer for each body area. In the example below, I've created a .dds file with the same dimensions as a Female Body (I run 4x Body Mod, so the dimensions are 2048 x 4096). Add it as Diffuse Layer in a new skin layer. Repeat for each body area. And if you want an arm or leg a different colour, use a mask to, erm, mask the rest of the body you don't want visible and then add multiple skin layers for each body arm, leg, etc.  I forgot that mask only mask _spec & _norm layers, not diffuse layers. You'll just have to create a .png file and manually delete the area you don't want using Photoshop or some other program, leaving only the area you do want green (like an arm, or something).
 
I appreciate this isn't a very good explanation, but I just thought I'd throw it out there. Obviously, I don't know how familar you are with skin customisation, so let me know if you have any questions...
fembody.rar

I can't remember for certain if the hook data 11 folder belongs in the binaries folder (it probably does), but it sure doesn't belong in the base game folder! 😆
Hope this helps. 
Edit: Also, for some unknown reason, Pervokpetr still has the 2017 version of  Hook 5 Basic on his Patreon. I don't know if you downloaded Hook 5 Basic from here or the Patreon page, but here is the link to the 2019 version:
 

Photoshop is the best tool (IMHO) to create _spec and _norm files, but there are plenty of other programs that do the same job. There are even online sites that do it for you! I don't have the links at the moment, but you might be able to google them. 
As to assigning them... if we're talking Hook 5 Objects here, all you need to do it rename either the _spec or _norm file with the name of the texture file (be it a .dds/.png/.jpeg) and add _spec or _norm to the end. And that's it!

Yeah, this was fixed with the update. 😁