I've told you why that doesn't work. Because you cannot disable the 1 and 8 flags ( color and mipmapping ) without clearing texture filters. If you don't believe me, maybe you'll believe the help file which says :
Your wildcard texture filter doesn't work because it puts that filter back on that you just took off by clearing texture filters. You will need to make a texture filter for all the textures you want loaded with the 1+8 flags and rename the textures accordingly in order to be able to load one texture without one or more of those flags.
Something to consider when applying texture flags to loaded textures is that the texture may have already had certain flags applied to it via the TextureFilter command. The default for the TextureFilter command is 9 (1+8), which is a coloured, mipmapped texture. This cannot be overridden via the flags parameter of the LoadTexture command - if you wish for the filters to be removed you will need to use the ClearTextureFilters command, which must be done after setting the graphics mode (setting the graphics mode restores the default texture filters).
Your wildcard texture filter doesn't work because it puts that filter back on that you just took off by clearing texture filters. You will need to make a texture filter for all the textures you want loaded with the 1+8 flags and rename the textures accordingly in order to be able to load one texture without one or more of those flags.