> The transactional site allows in mode connected, to
> make insertion, update and suppressions in a distant
> database. 
> 
> Could you say that HTTRACK could download site which
> permit updates ?
HTTrack will follow links, but will not execute all the actions of a form. 
Also the order of mirroring can affect sessions.

It totally depends on how the site is written.  If these "transactions" are
not regular HTTP pages/scripts then you are probably going to have trouble.