> I guess the server doesn't like these 2 variables together
> with the PHPSESSID, because the browser sends it alone.
> Is there a way to modify the cookie file so that httrack
> sends only the variables that I want?
Use the 'Capture URL' feature, AFTER clearing all your 
cookies, which will force a re-authentication. This should 
do the trick. If necessary, you can edit the 'postfile' 
generated by httrack in the project folder (which is a 
regular HTTP request, in ascii)