Submit Pdf form to http w/ credentials (username/password)

Hi!

I developed a form in Adobe LiveCycle, it has a button which submits form with attachments to http site.

No coding involved, just configuration of the button.

Http site requires credentials (username/password). How do I pass those credentials with submission?

Can username/password be added to http header?

Or I can excecute some javascript before submission?

Thanks you!