This is a mental note to myself but perhaps some of you Swat 3 mod guys can figure this one out.
Originally all of the Last Resort mod files were loaded almost as they were game system files ( ie. Swatdata.res ). The only problem discovered with this is that unfortunately the original developers got sloppy and re-used some of the same textures (and filenames) in later missions. This created a problem when I wanted to replace textures with high resolution versions. Sometimes the new texture was ignored because textures in the missions folder had a higher priority.
I moved the Last Resort textures into the mod folder (not an ideal situation) to give the textures higher load priority but this may actually cause problems with single player "campaign" missions. I need to test further.
Possible solution: actually move the textures to the mission folder like I did with the Deceiver 2 mod long ago.