http://www.noxgeo.com/ww3d/links.html does contain under "Props" a 1939-1945 type UK "tin hat" and also a USA GI steel helmet (as well as a mass of German stuff). But its German steel helmet (called "SS Stahlhelm") was 404 when I looked just now. There is a German-style helmet in the Poser Fun Stuff (with texture map to put your own badge on it) (and with a posable anachronistic transparent riotsquad visor, but delete/hide the visor if you don't want it).