just to tell you, the wc3 viewer is a horrible tool. It doesn't display particles and their path correctly, its messy and I absolutly hate it. And the blue burns my eyes. It might have some small useful functions I didn't see, but honeslty, there is way better.
Wc3 model editor can do the same thing plus:
-edit geometry
-actually show particles correctly
-all that geoset animations, sequence and node stuff
-add extra lights and emitters.
maybe you didn't put the texture in the right file or something. wc3 model editor never did that to me.