First, lets have a brief explanation of how the new in-game camo patterns work in 7.0.
Right, so what if you want to keep using player made custom skins?
There are 2 methods of doing it:
1. Blacken the CM file of whichever vehicle you don't want dev-made camo skins to appear on.
2. Blacken every channel of all camo files found in the ..\(game install folder)\res\vehicles\(nation)\Camouflage folder (note that this method will affect all tanks instead of specific tanks).
As you can see below I have a custom skin installed for my Leopard. On the left side is how it looks like without any dev-made camo pattern applied. On the right side is how it looks like with a dev-made camo pattern applied:
As you can see the custom skin looks messed up with the new dev-made camo pattern overlaid on top of it. Of course, one might say the solution to this problem is to simply not use the new dev-made camo pattern on your tank. However, if you are using a custom skin on a certain tank other players you see in battle who opt to use the dev-made camo pattern on the same tank(s) as you are will appear messed up!
So in order to be able to use custom skins without it appearing messed up whenever a dev-made camo pattern is applied you will have to edit/replace the tank's CM file. As you can see from the image below my custom skill still looks okay even though a dev-made camo pattern is selected (the pattern box is highlighted):
This is what the Leopards's CM file (VK1602_CM.dds) looks like before and after editing:
It should be noted that the CM files apparently have alpha information inside it, so if you want to preserve it for each tank you have to save it as "DXT1 with Alpha" from the original CM file. However there doesn't seem to be any adverse effects with simply discarding the alpha because by making it all black in effect you don't want to use the default patterns so any alpha info within the file becomes irrelevant. This means that we could simply use a 100% black no-alpha CM file and use it for every tank which we don't want to have dev-made camo patterns applied to it. I've uploaded a blank file for anyone who wants to give it a try:
To use it, open your vehicle's folder (e.g. ..WoT\res\vehicles\german\G26_VK1602) and back up the original CM file. Then copy the blank CM file into the folder and rename it according to the original file name (e.g. in the leopard's case it's VK1602_CM.dds). Now any custom skins you use on the tank will be displayed correctly even when dev-made camo patterns are applied. The only downside is that you can't see if someone is using an dev-made camo skin on that tank rather than just having a default base skin.
Note: that this method of blackening the CM file will only affect the particular tank you're editing (useful if you want to retain the dev-made camo patterns for other tanks).
In one of the posts below I've also described how you can edit the in-game camouflage patterns. It's then possible to disable dev-made camo patterns for EVERY tank by blackening each nation's camo tiles.
And now we know how skins work in 7.0 we can all continue skinning and using new custom skins as usual : D
I hope all skinners and custom skin users will find this guide helpful, any questions just post a reply in this thread.