Hi Manuel,
I like the dagger. I have some reservations, mostly about the ebony grip, but overall it seems like its construction is fairly consistant throughout, medium quality, slightly more elaborate than would be expected.
The pommel does appear to be a 18thC style urn pommel, but the more I look at it the more I just wonder if its a bit of a hybrid of 17thC styles?
The closest I can find is on a Hungarian executioners sword from about 1620.

But there are other swords and daggers from the 17th that do have some similarities to the urn form, this could just be a slightly skewed interpretation of one of those forms made by a medium skilled artisan. (Just an idea)

Pappenheimers seem to sometimes have pommels that are more asymetric and 'urn like'.