Note, though, that this disables creation of mipmaps. If you created a texture with mipmaps (intentionally, or due to loading from a .irr file), you can also disable use of mipmaps (also temporarily). This flag is rather new, so I'm not sure whether it's already part of Irrlicht 1.7
Yes, indeed one of the points I wanted to fix with this flag was the 'skybox from .irr files' problem. It's useful in other places as well. A proper fix for the actual problem would be to have serializable texture creation flags and methods to work with the mipmap settings of the texture, though. Will come later.