Okay, I think I know why you're refusing to allow that Wiccan soldier to have the most well-known symbol of Wicca on his headstone. It's because of its supposed resemblance to the "Satanic" pentacle, isn't it?
Well, I have a suggestion for how to appease the soldier's family and yet not have a pentacle in your cemetary: use one of the other symbols of Wicca. One in particular should satisfy everyone: http://img.photobucket.com/albums/v379/Fayanora/triplemoon.gif
See? Now that's inoffensive to all, isn't it?
---Tristan A. Arts