I think that the Hamburg connection started because Celtic have a connection with St Pauli. They are both arch rivals with St Pauli claiming Hamburg are Nazi's just as the tims do with us. It seems it is not just Germany but if you look on the website from DB there are also links to Russian Rangers websites. I would think that having the army so long in Germany and so many expats living there has also got some support. While I can't claim any of my circle have become Rangers supporters they do have a softer spot for Rangers through knowing me.