I suspect....
...Germany has become the first country to recognise Bitcoin as a real form of currency, which will be subject to tax like any other dosh....
...that ALL countries already recognise Bitcoins in practice.
In the UK the tax authorities are perfectly capable of levying tax on remuneration paid 'in kind', and do so regularly. If I decided to run a company and get paid in Bitcoins I would be required to post company accounts in the usual fashion, and I am sure that the Revenue would simply treat Bitcoins as a payment in kind with a suitable exchange rate. Exactly the same as if I had asked to be paid in butter or some other commodity.
And since commodity trade has been going on for eons, I am sure that no country would have a difficulty taxing it. All that has happened here is that the German authorities have mentioned it in a publication.
Things don't have to be 'currency' to be taxed.....