There used to be a helmet at 3DCafe, but they still haven't fixed their freebie area.

I was going to recommend the old Michael 2 75th Ranger, by Billy-T, but that's no longer available here.

There really isn't a good modern soldier Poser combat figure on the market that I'm aware of.

My visual indexes of Poser content are at http://www.sharecg.com/pf/rgagnon