Is it possible to simply swap out an old incandescent front light with any sort of halogen light, or are there specific "compatibility requirements" for the dynamo and rear light used?

My setup consists of:

• A Union model 4290 incandescent front light which was just KO'ed and needs replacing*
• A 2-month-old Busch & Müller 339AS incandescent rear light*
• An old Soubitez 6v/3w bottle dynamo which (usually) manages to light the two lights above fine**

Since the front light is dead, I saw that the price of a cheap halogen light needn't be much more than that of a cheap incandescent. Could I simply just attach one, or does it need more power/different resistance/etc.?

* Interesting that the website has a little flag apparently for an English translation... which happens to to do nothing. Anyway, there's nothing special about these cheap lights: I simply wanted to link to an image of them.
** While browsing teh Internets, I just noticed that these dynamos are being sold for a ridiculous amount of money... So it seems my next question is now: How do you refurbish old bottle dynamos?