Once you reach level 50, speak to Lieutenant John H. Miller at A British Aid Station and ask him "HERO", then agree to his mission. He will ask you to help thin down the enemy numbers and bring him 25 German wehrpass as proof of kills. Once you give him 25 wehrpass (one at a time or he loses count) you will gain exp and the whois.
If you want the Legion of Merit ask Miller reward and then type YES, then you will loose 15,000,000 Xp, but in exchange you will get the Legion of Merit!
NOTE: You need to have 40,000,000 XP or more to get the item.