I just purchased an Airport Express and I am trying to set up one specific folder that can I can share to a friend logging in from a different network. I had it set up and working flawlessly using with the old Linksys router that I just replaced, but cannot, for the life of me, figure out how to configure this setup now that I am using the Airport Express. I am using an iMac running Mountain Lion and my friend is using a Macbook running Lion. Any ideas would be greatly appreciated! THanks!