Not quite the same, but I used that Assyrian Allied Infantry set for modeling the
earlier Bronze Age Assyrians as opponents for my Hittites and others:
I don't see why you couldn't use some for vassal troops from the more easterly parts of the Hittite empire; they're fairly generic-looking. I did end up trimming the helmet plumes off of most of them, and I used the round shields rather than the tall ones; I think the latter are more from the later period. As an alternative, you might notice a few converted Airfix Robin Hood figures mixed in there; I have some others who have long served as generic Bronze Age levies: