It seems that Famitsu has revealed the secret password for Metal Gear Solid 4 that will allow you to obtain Altair's costume from Assassin's Creed without the assassin's emblem. To obtain it, go to the password section and enter in aottrykmyn. Once this password is activated, you can jump into Altair’s costume from the camouflage menu after you get the Metal Gear Mk. II. Another password you can enter is jmsotsynrn. Once you enter that, you will be able to yield the Type 17 pistol. Have fun with these new items!