> Some web sites are protected with a login & password. And 
in
> these sites there is  a research function with a form to 
fill.
> In fact, there are 2 form to post.
> The first for the identification, the second for the 
research.
> Is it possible to do that with HTrack?
No - you'll only get the first one. You may try to copy the 
authentication cookie, if it exists, but the result is not 
guaranteed.