Not an easy answer to find, however, AutoIT is capable of allowing secure HTTP, FTP, or HTTPS downloads using a script. The following script worked for me.
#include ;Sample script to download registered files from HTTP source. ;Internet Explorer used to offer the ability via http://username:email@example.com InetGet("http://username:firstname.lastname@example.org/downloadme.exe", "downloadme.exe", 1) ;note: That there is no progressbar to indicate download. ;note: This script will download the executable to the same folder as the script.