Attached Link: http://www.renderosity.com/mod/bcs/index.php?ViewProduct=149

Check these out - these are one of the very first things I purchased for Poser - God knows how many years ago - Thet're made for the Poser 4 woman but with a little bit of rescaling they can be used on any figure.

...or if you do a search for helmet, here on Rendo or at RDNA, I'm sure you'll find something for free that's suitable...