A little confused about skin codes

[Sapphire.x]

I've noticed that only a small amount of skin codes work properly on mine and Dizzy's BT server.

By skin codes I mean changing the User.ini line:

[DefaultPlayer]
skin=texture name

I have seen people using genfluid.lava and this works fine, but if I try genfluid.water then this doesn't work. I tried using the water skin on other servers and it displayed correctly. It also works offline when not in a team game (I'm assuming it forces team colours).

Has anyone come across this issue before?

Edit: Here's what it says in the server log when I join using the genfluid.water skin:

Failed to load genfluid.Water.WATE44 so load SoldierSkins.blkt4
Failed to load 'Texture genfluid.WATE44': Failed to find object 'Texture genfluid.WATE44'
Failed to load genfluid.Water.WATE3 so load SoldierSkins.blkt3
Failed to load 'Texture genfluid.WATE3': Failed to find object 'Texture genfluid.WATE3'
Failed to load 'Texture SGirlSkins.water5Cathode': Failed to find object 'Texture SGirlSkins.water5Cathode'
Failed to load genfluid.water2T_0 so load genfluid.water2
Failed to load 'Texture genfluid.water2T_0': Failed to find object 'Texture genfluid.water2T_0'
Failed to load genfluid.water1T_0 so load genfluid.water1
Failed to load 'Texture genfluid.water1T_0': Failed to find object 'Texture genfluid.water1T_0'
Failed to load SGirlSkins.water4Cathode so load genfluid.water4
Failed to load 'Texture SGirlSkins.water4Cathode': Failed to find object 'Texture SGirlSkins.water4Cathode'
Attempted to use illegal skin from package SGirlSkins for Soldier
Login: Sapphire

Clearly something is amiss. I just don't understand why lava works and water doesn't.

[UTrustedPlayer]

Look for a mod called val avatar and install it on your server. If you want me to explain why that works then I will but if you just want it to work then do that.

[Sapphire.x]

Thanks for the reply - and yes I would like you to explain if you don't mind.

With the help of Dizzy I saw that in the Engine.Pawn source code there's something called CheckValidSkinPackage, but I am not really familiar with uscript so it makes little sense to me.

What still confuses me is why the lava textures are "unprotected" skins and the water textures aren't.