I guess, you can hardcode the target url inside the form using a form
submit element. The best practise would be, the url should first take to
your client application, and from there you can invoke the LiveCycle
process to process the form. However, I am not sure of authenication
part . If the submit request comes from a web page and If the
application is already secured (https protocol), it would automatically
prompt the user to login page. Not sure, of how it would work on submit
from a pdf do...