I have MagicFPS. This may or may not help, but here is four screenies making a door.
The following image is magicFPS door mode. There is only one texture required.
The next image shows my picking a default door image.
This image shows the door placed in a level.
And the final image shows the door open.
Addendum:
Here is a door example of the texture layout given by magicFPS:
I hope you can make out how it's layed out. I'm not sure I can.
The past has a lot of memories to hold onto; but, today is chock full of new adventures, and, the future shouts out, "The best is yet to come!" -- TerryC