New developings:

the problem is not that it should match the original file. 
I was wrong, it must not match, in deed.

The problem is that the server gets misleaded by the two 
questions marks, when HTTrack follows the link. In the 
example I gave in the original mail, there isn't a problem 
with the two question marks (so it is a bad example, after 
all), but with the site i'm developing there is, because 
the query string is not properly interpreted.