first, you should confirm with you seller is your model can use external 3G modem(dango?).
many android tablets now, hard to use 3G dango. the problem is android os. we tested many models. for example, X dango can be used on A model, but not sure is can be sued on B model.
is you model support external 3G modem, you can find the option:3G, choose it , it will tell you which 3G model can be supported.
As far as I am aware, it does not work as the drivers are not yet supported for any 3G modems. However you can use a Huawei E585 Mifi adapter as a wireless hotspot which I have used with my Archos 101 without problem in England, Ireland and USA. You should be able to find these unlocked fairly easily in Europe. I paid around £70 for mine.